Find an element in a sorted and rotated array
In computer science, the problem of finding an element in a sorted and rotated array is a common challenge. The array is initially sorted in ascending order and then rotated at some pivot point, where the elements to the right of the pivot come before the elements to the left. The task is to efficiently locate a given target element in the rotated array.
Problem Statement
Given a sorted and rotated array arr, we need to find the index of a target element k in
the array. If the element is present, the algorithm should return the index of the target element; otherwise, it
should return -1.
Explanation with Example
Let's take the array arr = [7, 8, 9, 1, 2, 3, 4, 5, 6] as an example. The array is sorted in ascending
order initially, but it has been rotated at the pivot point between 9 and 1. If we want to find the element 2, the
algorithm should return index 4. Similarly, for element 9, the algorithm should return index 2.
Pseudocode
The following is the standard pseudocode for the algorithm to find an element in a sorted and rotated array:
1. Function binarySearch(arr, k, low, high)
2. If low > high
3. Return -1
4. Else
5. mid = (low + high) / 2
6. If arr[mid] == k
7. Return mid
8. If arr[low] < arr[mid]
9. If k >= arr[low] AND k < arr[mid]
10. Return binarySearch(arr, k, low, mid - 1)
11. Else
12. Return binarySearch(arr, k, mid + 1, high)
13. Else If arr[mid] < arr[high]
14. If k > arr[mid] AND k <= arr[high]
15. Return binarySearch(arr, k, mid + 1, high)
16. Else
17. Return binarySearch(arr, k, low, mid - 1)
18. Else If arr[low] == arr[mid]
19. If arr[mid] != arr[high]
20. Return binarySearch(arr, k, mid + 1, high)
21. Else
22. result = binarySearch(arr, k, low, mid - 1)
23. If result == -1
24. result = binarySearch(arr, k, mid + 1, high)
25. Return result
Algorithm Explanation
The algorithm is a variation of the binary search algorithm. It takes a sorted and rotated array arr,
the target element k, and the low and high indices of the array as input. It searches for the target
element k in the array and returns the index of the element if found, or -1 if not found.
The binarySearch function first checks if the low index is greater than the high index, which means the target
element is not present, and it returns -1. Otherwise, it calculates the mid index and compares the element at the
mid index with the target element k.
If the element at the mid index is equal to the target element k, it means the element is found, and the
function returns the mid index.
If the element at the low index is less than the element at the mid index, it implies that the elements from
low to mid are in sorted order. In this case, the algorithm checks if the target element
k falls within this range. If it does, the algorithm performs a recursive binary search on the left
half of the array (from low to mid-1); otherwise, it performs a recursive binary search on
the right half of the array (from mid+1 to high).
Similarly, if the element at the mid index is less than the element at the high index, it means the elements from
mid to high are in sorted order. The algorithm checks if the target element k
falls within this range and proceeds with the recursive binary search accordingly.
If the elements at both the low and mid indices are equal, it indicates that there are repeated elements in the array. The algorithm checks if the element at the mid index is different from the element at the high index to decide which side to perform the recursive binary search. If the element at the mid index is also equal to the element at the high index, it means we need to check both the left and right subtrees to find the target element.
Program Solution
// C Program
// Find an element in a sorted and rotated array
#include <stdio.h>
// Display array elements
void display(int arr[], int size)
{
printf("\n\n Array Elements \n [");
for (int i = 0; i < size; ++i)
{
printf(" %d", arr[i]);
}
printf(" ]\n");
}
// Finding the element location of sorted rotated array
int binarySearch(int arr[], int k, int low, int high)
{
if (low > high)
{
return -1;
}
else
{
int mid = (low + high) / 2;
if (arr[mid] == k)
{
// When element exist
return mid;
}
if (arr[low] < arr[mid])
{
// When elements are sort in location low to mid position
if (k >= arr[low] && k < arr[mid])
{
// When the element is possible in the (low) to (mid-1) position
return binarySearch(arr, k, low, mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return binarySearch(arr, k, mid + 1, high);
}
}
else if (arr[mid] < arr[high])
{
if (k > arr[mid] && k <= arr[high])
{
// When the element is possible in the (mid+1) to (high) position
return binarySearch(arr, k, mid + 1, high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return binarySearch(arr, k, low, mid - 1);
}
}
else if (arr[low] == arr[mid])
{
// When repeated array element exists
if (arr[mid] != arr[high])
{
return binarySearch(arr, k, mid + 1, high);
}
else
{
// Check if that element exists in left subtree
int result = binarySearch(arr, k, low, mid - 1);
if (result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
result = binarySearch(arr, k, mid + 1, high);
}
return result;
}
}
}
}
void findElement(int arr[], int size, int k)
{
int location = binarySearch(arr, k, 0, size - 1);
if (location == -1)
{
printf("\n Element %d Are not exist ", k);
}
else
{
printf("\n Element %d exist in location %d ", k, location);
}
}
int main()
{
// Defining sorted and rotated array of integer element
int arr1[] = {
7 , 8 , 9 , 1 , 2 , 3 , 4 , 5 , 6
};
int arr2[] = {
11 , 22 , 43 , 45 , 51 , 62 , 73 , 1 , 9 , 10
};
// Get the size
int size = sizeof(arr1) / sizeof(arr1[0]);
display(arr1, size);
findElement(arr1, size, 9);
findElement(arr1, size, 3);
// Get the size
size = sizeof(arr2) / sizeof(arr2[0]);
display(arr2, size);
// Test Case B (of arr2)
findElement(arr2, size, 9);
findElement(arr2, size, 11);
findElement(arr2, size, 67);
return 0;
}Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist/*
Java program
Find an element in a sorted and rotated array
*/
public class SearchElement
{
// Display array elements
public void display(int[] arr, int size)
{
System.out.print("\n\n Array Elements \n [");
for (int i = 0; i < size; ++i)
{
System.out.print(" " + arr[i]);
}
System.out.print(" ]\n");
}
// Finding the element location of sorted rotated array
public int binarySearch(int[] arr, int k, int low, int high)
{
if (low > high)
{
return -1;
}
else
{
int mid = (low + high) / 2;
if (arr[mid] == k)
{
// When element exist
return mid;
}
if (arr[low] < arr[mid])
{
// When elements are sort in location low to mid position
if (k >= arr[low] && k < arr[mid])
{
// When the element is possible in the (low) to (mid-1) position
return binarySearch(arr, k, low, mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return binarySearch(arr, k, mid + 1, high);
}
}
else if (arr[mid] < arr[high])
{
if (k > arr[mid] && k <= arr[high])
{
// When the element is possible in the (mid+1) to (high) position
return binarySearch(arr, k, mid + 1, high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return binarySearch(arr, k, low, mid - 1);
}
}
else if (arr[low] == arr[mid])
{
// When repeated array element exists
if (arr[mid] != arr[high])
{
return binarySearch(arr, k, mid + 1, high);
}
else
{
// Check if that element exists in left subtree
int result = binarySearch(arr, k, low, mid - 1);
if (result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
result = binarySearch(arr, k, mid + 1, high);
}
return result;
}
}
}
return -1;
}
// Handle request to find array elements
public void findElement(int[] arr, int size, int k)
{
int location = binarySearch(arr, k, 0, size - 1);
if (location == -1)
{
System.out.print("\n Element " + k + " Are not exist ");
}
else
{
System.out.print("\n Element " + k + " exist in location " + location);
}
}
public static void main(String[] args)
{
SearchElement task = new SearchElement();
// Defining sorted and rotated array of integer element
int[] arr1 = {
7 , 8 , 9 , 1 , 2 , 3 , 4 , 5 , 6
};
int[] arr2 = {
11 , 22 , 43 , 45 , 51 , 62 , 73 , 1 , 9 , 10
};
// Get the size
int size = arr1.length;
task.display(arr1, size);
// Test Cases
task.findElement(arr1, size, 9);
task.findElement(arr1, size, 3);
// Get the size
size = arr2.length;
task.display(arr2, size);
// Test Cases
task.findElement(arr2, size, 9);
task.findElement(arr2, size, 11);
task.findElement(arr2, size, 67);
}
}Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist// Include header file
#include <iostream>
using namespace std;
/*
C++ program
Find an element in a sorted and rotated array
*/
class SearchElement
{
public:
// Display array elements
void display(int arr[], int size)
{
cout << "\n\n Array Elements \n [";
for (int i = 0; i < size; ++i)
{
cout << " " << arr[i];
}
cout << " ]";
}
// Finding the element location of sorted rotated array
int binarySearch(int arr[], int k, int low, int high)
{
if (low > high)
{
return -1;
}
else
{
int mid = (low + high) / 2;
if (arr[mid] == k)
{
// When element exist
return mid;
}
if (arr[low] < arr[mid])
{
// When elements are sort in location low to mid position
if (k >= arr[low] && k < arr[mid])
{
// When the element is possible in the (low) to (mid-1) position
return this->binarySearch(arr, k, low, mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return this->binarySearch(arr, k, mid + 1, high);
}
}
else if (arr[mid] < arr[high])
{
if (k > arr[mid] && k <= arr[high])
{
// When the element is possible in the (mid+1) to (high) position
return this->binarySearch(arr, k, mid + 1, high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return this->binarySearch(arr, k, low, mid - 1);
}
}
else if (arr[low] == arr[mid])
{
// When repeated array element exists
if (arr[mid] != arr[high])
{
return this->binarySearch(arr, k, mid + 1, high);
}
else
{
// Check if that element exists in left subtree
int result = this->binarySearch(arr, k, low, mid - 1);
if (result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
result = this->binarySearch(arr, k, mid + 1, high);
}
return result;
}
}
}
return -1;
}
// Handle request to find array elements
void findElement(int arr[], int size, int k)
{
int location = this->binarySearch(arr, k, 0, size - 1);
if (location == -1)
{
cout << "\n Element " << k << " Are not exist ";
}
else
{
cout << "\n Element " << k << " exist in location " << location;
}
}
};
int main()
{
SearchElement task = SearchElement();
// Defining sorted and rotated array of integer element
int arr1[] = {
7 , 8 , 9 , 1 , 2 , 3 , 4 , 5 , 6
};
int arr2[] = {
11 , 22 , 43 , 45 , 51 , 62 , 73 , 1 , 9 , 10
};
// Get the size
int size = sizeof(arr1) / sizeof(arr1[0]);
task.display(arr1, size);
// Test Cases
task.findElement(arr1, size, 9);
task.findElement(arr1, size, 3);
// Get the size
size = sizeof(arr2) / sizeof(arr2[0]);
task.display(arr2, size);
// Test Cases
task.findElement(arr2, size, 9);
task.findElement(arr2, size, 11);
task.findElement(arr2, size, 67);
return 0;
}Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist// Include namespace system
using System;
/*
C# program
Find an element in a sorted and rotated array
*/
public class SearchElement
{
// Display array elements
public void display(int[] arr, int size)
{
Console.Write("\n\n Array Elements \n [");
for (int i = 0; i < size; ++i)
{
Console.Write(" " + arr[i]);
}
Console.Write(" ]");
}
// Finding the element location of sorted rotated array
public int binarySearch(int[] arr, int k, int low, int high)
{
if (low > high)
{
return -1;
}
else
{
int mid = (low + high) / 2;
if (arr[mid] == k)
{
// When element exist
return mid;
}
if (arr[low] < arr[mid])
{
// When elements are sort in location low to mid position
if (k >= arr[low] && k < arr[mid])
{
// When the element is possible in the (low) to (mid-1) position
return binarySearch(arr, k, low, mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return binarySearch(arr, k, mid + 1, high);
}
}
else if (arr[mid] < arr[high])
{
if (k > arr[mid] && k <= arr[high])
{
// When the element is possible in the (mid+1) to (high) position
return binarySearch(arr, k, mid + 1, high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return binarySearch(arr, k, low, mid - 1);
}
}
else if (arr[low] == arr[mid])
{
// When repeated array element exists
if (arr[mid] != arr[high])
{
return binarySearch(arr, k, mid + 1, high);
}
else
{
// Check if that element exists in left subtree
int result = binarySearch(arr, k, low, mid - 1);
if (result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
result = binarySearch(arr, k, mid + 1, high);
}
return result;
}
}
}
return -1;
}
// Handle request to find array elements
public void findElement(int[] arr, int size, int k)
{
int location = binarySearch(arr, k, 0, size - 1);
if (location == -1)
{
Console.Write("\n Element " + k + " Are not exist ");
}
else
{
Console.Write("\n Element " + k + " exist in location " + location);
}
}
public static void Main(String[] args)
{
SearchElement task = new SearchElement();
// Defining sorted and rotated array of integer element
int[] arr1 = {
7 , 8 , 9 , 1 , 2 , 3 , 4 , 5 , 6
};
int[] arr2 = {
11 , 22 , 43 , 45 , 51 , 62 , 73 , 1 , 9 , 10
};
// Get the size
int size = arr1.Length;
task.display(arr1, size);
// Test Cases
task.findElement(arr1, size, 9);
task.findElement(arr1, size, 3);
// Get the size
size = arr2.Length;
task.display(arr2, size);
// Test Cases
task.findElement(arr2, size, 9);
task.findElement(arr2, size, 11);
task.findElement(arr2, size, 67);
}
}Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist<?php
/*
Php program
Find an element in a sorted and rotated array
*/
class SearchElement
{
// Display array elements
public function display( & $arr, $size)
{
echo "\n\n Array Elements \n [";
for ($i = 0; $i < $size; ++$i)
{
echo " ". $arr[$i];
}
echo " ]";
}
// Finding the element location of sorted rotated array
public function binarySearch( & $arr, $k, $low, $high)
{
if ($low > $high)
{
return -1;
}
else
{
$mid = intval(($low + $high) / 2);
if ($arr[$mid] == $k)
{
// When element exist
return $mid;
}
if ($arr[$low] < $arr[$mid])
{
// When elements are sort in location low to mid position
if ($k >= $arr[$low] && $k < $arr[$mid])
{
// When the element is possible in the (low) to (mid-1) position
return $this->binarySearch($arr, $k, $low, $mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return $this->binarySearch($arr, $k, $mid + 1, $high);
}
}
else if ($arr[$mid] < $arr[$high])
{
if ($k > $arr[$mid] && $k <= $arr[$high])
{
// When the element is possible in the (mid+1) to (high) position
return $this->binarySearch($arr, $k, $mid + 1, $high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return $this->binarySearch($arr, $k, $low, $mid - 1);
}
}
else if ($arr[$low] == $arr[$mid])
{
// When repeated array element exists
if ($arr[$mid] != $arr[$high])
{
return $this->binarySearch($arr, $k, $mid + 1, $high);
}
else
{
// Check if that element exists in left subtree
$result = $this->binarySearch($arr, $k, $low, $mid - 1);
if ($result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
$result = $this->binarySearch($arr, $k, $mid + 1, $high);
}
return $result;
}
}
}
return -1;
}
// Handle request to find array elements
public function findElement( & $arr, $size, $k)
{
$location = $this->binarySearch($arr, $k, 0, $size - 1);
if ($location == -1)
{
echo "\n Element ". $k ." Are not exist ";
}
else
{
echo "\n Element ". $k ." exist in location ". $location;
}
}
}
function main()
{
$task = new SearchElement();
// Defining sorted and rotated array of integer element
$arr1 = array(7, 8, 9, 1, 2, 3, 4, 5, 6);
$arr2 = array(11, 22, 43, 45, 51, 62, 73, 1, 9, 10);
// Get the size
$size = count($arr1);
$task->display($arr1, $size);
// Test Cases
$task->findElement($arr1, $size, 9);
$task->findElement($arr1, $size, 3);
// Get the size
$size = count($arr2);
$task->display($arr2, $size);
// Test Cases
$task->findElement($arr2, $size, 9);
$task->findElement($arr2, $size, 11);
$task->findElement($arr2, $size, 67);
}
main();Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist/*
Node Js program
Find an element in a sorted and rotated array
*/
class SearchElement
{
// Display array elements
display(arr, size)
{
process.stdout.write("\n\n Array Elements \n [");
for (var i = 0; i < size; ++i)
{
process.stdout.write(" " + arr[i]);
}
process.stdout.write(" ]");
}
// Finding the element location of sorted rotated array
binarySearch(arr, k, low, high)
{
if (low > high)
{
return -1;
}
else
{
var mid = parseInt((low + high) / 2);
if (arr[mid] == k)
{
// When element exist
return mid;
}
if (arr[low] < arr[mid])
{
// When elements are sort in location low to mid position
if (k >= arr[low] && k < arr[mid])
{
// When the element is possible in the (low) to (mid-1) position
return this.binarySearch(arr, k, low, mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return this.binarySearch(arr, k, mid + 1, high);
}
}
else if (arr[mid] < arr[high])
{
if (k > arr[mid] && k <= arr[high])
{
// When the element is possible in the (mid+1) to (high) position
return this.binarySearch(arr, k, mid + 1, high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return this.binarySearch(arr, k, low, mid - 1);
}
}
else if (arr[low] == arr[mid])
{
// When repeated array element exists
if (arr[mid] != arr[high])
{
return this.binarySearch(arr, k, mid + 1, high);
}
else
{
// Check if that element exists in left subtree
var result = this.binarySearch(arr, k, low, mid - 1);
if (result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
result = this.binarySearch(arr, k, mid + 1, high);
}
return result;
}
}
}
return -1;
}
// Handle request to find array elements
findElement(arr, size, k)
{
var location = this.binarySearch(arr, k, 0, size - 1);
if (location == -1)
{
process.stdout.write("\n Element " + k + " Are not exist ");
}
else
{
process.stdout.write("\n Element " + k + " exist in location " + location);
}
}
}
function main()
{
var task = new SearchElement();
// Defining sorted and rotated array of integer element
var arr1 = [7, 8, 9, 1, 2, 3, 4, 5, 6];
var arr2 = [11, 22, 43, 45, 51, 62, 73, 1, 9, 10];
// Get the size
var size = arr1.length;
task.display(arr1, size);
// Test Cases
task.findElement(arr1, size, 9);
task.findElement(arr1, size, 3);
// Get the size
size = arr2.length;
task.display(arr2, size);
// Test Cases
task.findElement(arr2, size, 9);
task.findElement(arr2, size, 11);
task.findElement(arr2, size, 67);
}
main();Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist# Python 3 program
# Find an element in a sorted and rotated list
class SearchElement :
# Display array elements
def display(self, arr, size) :
print("\n\n Array Elements \n [", end = "")
i = 0
while (i < size) :
print(" ", arr[i], end = "")
i += 1
print(" ]", end = "")
# Finding the element location of sorted rotated array
def binarySearch(self, arr, k, low, high) :
if (low > high) :
return -1
else :
mid = int((low + high) / 2)
if (arr[mid] == k) :
# When element exist
return mid
if (arr[low] < arr[mid]) :
# When elements are sort in location low to mid position
if (k >= arr[low] and k < arr[mid]) :
# When the element is possible in the (low) to (mid-1) position
return self.binarySearch(arr, k, low, mid - 1)
else :
# When the element is possible in the (mid+1) to (high) position
return self.binarySearch(arr, k, mid + 1, high)
elif(arr[mid] < arr[high]) :
if (k > arr[mid] and k <= arr[high]) :
# When the element is possible in the (mid+1) to (high) position
return self.binarySearch(arr, k, mid + 1, high)
else :
# When the element is possible in the (low) to (mid-1) position
return self.binarySearch(arr, k, low, mid - 1)
elif(arr[low] == arr[mid]) :
# When repeated array element exists
if (arr[mid] != arr[high]) :
return self.binarySearch(arr, k, mid + 1, high)
else :
# Check if that element exists in left subtree
result = self.binarySearch(arr, k, low, mid - 1)
if (result == -1) :
# When element not exist in left subtree then
# Check that element exists in right subtree
result = self.binarySearch(arr, k, mid + 1, high)
return result
return -1
# Handle request to find array elements
def findElement(self, arr, size, k) :
location = self.binarySearch(arr, k, 0, size - 1)
if (location == -1) :
print("\n Element ", k ," Are not exist ", end = "")
else :
print("\n Element ", k ," exist in location ", location, end = "")
def main() :
task = SearchElement()
# Defining sorted and rotated array of integer element
arr1 = [7, 8, 9, 1, 2, 3, 4, 5, 6]
arr2 = [11, 22, 43, 45, 51, 62, 73, 1, 9, 10]
# Get the size
size = len(arr1)
task.display(arr1, size)
# Test Cases
task.findElement(arr1, size, 9)
task.findElement(arr1, size, 3)
# Get the size
size = len(arr2)
task.display(arr2, size)
# Test Cases
task.findElement(arr2, size, 9)
task.findElement(arr2, size, 11)
task.findElement(arr2, size, 67)
if __name__ == "__main__": main()Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist# Ruby program
# Find an element in a sorted and rotated array
class SearchElement
# Display array elements
def display(arr, size)
print("\n\n Array Elements \n [")
i = 0
while (i < size)
print(" ", arr[i])
i += 1
end
print(" ]")
end
# Finding the element location of sorted rotated array
def binarySearch(arr, k, low, high)
if (low > high)
return -1
else
mid = (low + high) / 2
if (arr[mid] == k)
# When element exist
return mid
end
if (arr[low] < arr[mid])
# When elements are sort in location low to mid position
if (k >= arr[low] && k < arr[mid])
# When the element is possible in the (low) to (mid-1) position
return self.binarySearch(arr, k, low, mid - 1)
else
# When the element is possible in the (mid+1) to (high) position
return self.binarySearch(arr, k, mid + 1, high)
end
elsif(arr[mid] < arr[high])
if (k > arr[mid] && k <= arr[high])
# When the element is possible in the (mid+1) to (high) position
return self.binarySearch(arr, k, mid + 1, high)
else
# When the element is possible in the (low) to (mid-1) position
return self.binarySearch(arr, k, low, mid - 1)
end
elsif(arr[low] == arr[mid])
# When repeated array element exists
if (arr[mid] != arr[high])
return self.binarySearch(arr, k, mid + 1, high)
else
# Check if that element exists in left subtree
result = self.binarySearch(arr, k, low, mid - 1)
if (result == -1)
# When element not exist in left subtree then
# Check that element exists in right subtree
result = self.binarySearch(arr, k, mid + 1, high)
end
return result
end
end
end
return -1
end
# Handle request to find array elements
def findElement(arr, size, k)
location = self.binarySearch(arr, k, 0, size - 1)
if (location == -1)
print("\n Element ", k ," Are not exist ")
else
print("\n Element ", k ," exist in location ", location)
end
end
end
def main()
task = SearchElement.new()
# Defining sorted and rotated array of integer element
arr1 = [7, 8, 9, 1, 2, 3, 4, 5, 6]
arr2 = [11, 22, 43, 45, 51, 62, 73, 1, 9, 10]
# Get the size
size = arr1.length
task.display(arr1, size)
# Test Cases
task.findElement(arr1, size, 9)
task.findElement(arr1, size, 3)
# Get the size
size = arr2.length
task.display(arr2, size)
# Test Cases
task.findElement(arr2, size, 9)
task.findElement(arr2, size, 11)
task.findElement(arr2, size, 67)
end
main()Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist /*
Scala program
Find an element in a sorted and rotated array
*/
class SearchElement
{
// Display array elements
def display(arr: Array[Int], size: Int): Unit = {
print("\n\n Array Elements \n [");
var i: Int = 0;
while (i < size)
{
print(" " + arr(i));
i += 1;
}
print(" ]");
}
// Finding the element location of sorted rotated array
def binarySearch(arr: Array[Int], k: Int, low: Int, high: Int): Int = {
if (low > high)
{
return -1;
}
else
{
var mid: Int = ((low + high) / 2).toInt;
if (arr(mid) == k)
{
// When element exist
return mid;
}
if (arr(low) < arr(mid))
{
// When elements are sort in location low to mid position
if (k >= arr(low) && k < arr(mid))
{
// When the element is possible in the (low) to (mid-1) position
return this.binarySearch(arr, k, low, mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return this.binarySearch(arr, k, mid + 1, high);
}
}
else if (arr(mid) < arr(high))
{
if (k > arr(mid) && k <= arr(high))
{
// When the element is possible in the (mid+1) to (high) position
return this.binarySearch(arr, k, mid + 1, high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return this.binarySearch(arr, k, low, mid - 1);
}
}
else if (arr(low) == arr(mid))
{
// When repeated array element exists
if (arr(mid) != arr(high))
{
return this.binarySearch(arr, k, mid + 1, high);
}
else
{
// Check if that element exists in left subtree
var result: Int = this.binarySearch(arr, k, low, mid - 1);
if (result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
result = this.binarySearch(arr, k, mid + 1, high);
}
return result;
}
}
}
return -1;
}
// Handle request to find array elements
def findElement(arr: Array[Int], size: Int, k: Int): Unit = {
var location: Int = this.binarySearch(arr, k, 0, size - 1);
if (location == -1)
{
print("\n Element " + k + " Are not exist ");
}
else
{
print("\n Element " + k + " exist in location " + location);
}
}
}
object Main
{
def main(args: Array[String]): Unit = {
var task: SearchElement = new SearchElement();
// Defining sorted and rotated array of integer element
var arr1: Array[Int] = Array(7, 8, 9, 1, 2, 3, 4, 5, 6);
var arr2: Array[Int] = Array(11, 22, 43, 45, 51, 62, 73, 1, 9, 10);
// Get the size
var size: Int = arr1.length;
task.display(arr1, size);
// Test Cases
task.findElement(arr1, size, 9);
task.findElement(arr1, size, 3);
// Get the size
size = arr2.length;
task.display(arr2, size);
// Test Cases
task.findElement(arr2, size, 9);
task.findElement(arr2, size, 11);
task.findElement(arr2, size, 67);
}
}Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist/*
Swift 4 program
Find an element in a sorted and rotated array
*/
class SearchElement
{
// Display array elements
func display(_ arr: [Int], _ size: Int)
{
print("\n\n Array Elements \n [", terminator: "");
var i: Int = 0;
while (i < size)
{
print(" ", arr[i], terminator: "");
i += 1;
}
print(" ]", terminator: "");
}
// Finding the element location of sorted rotated array
func binarySearch(_ arr: [Int], _ k: Int, _ low: Int, _ high: Int)->Int
{
if (low > high)
{
return -1;
}
else
{
let mid: Int = (low + high) / 2;
if (arr[mid] == k)
{
// When element exist
return mid;
}
if (arr[low] < arr[mid])
{
// When elements are sort in location low to mid position
if (k >= arr[low] && k < arr[mid])
{
// When the element is possible in the (low) to (mid-1) position
return self.binarySearch(arr, k, low, mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return self.binarySearch(arr, k, mid + 1, high);
}
}
else if (arr[mid] < arr[high])
{
if (k > arr[mid] && k <= arr[high])
{
// When the element is possible in the (mid+1) to (high) position
return self.binarySearch(arr, k, mid + 1, high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return self.binarySearch(arr, k, low, mid - 1);
}
}
else if (arr[low] == arr[mid])
{
// When repeated array element exists
if (arr[mid] != arr[high])
{
return self.binarySearch(arr, k, mid + 1, high);
}
else
{
// Check if that element exists in left subtree
var result: Int = self.binarySearch(arr, k, low, mid - 1);
if (result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
result = self.binarySearch(arr, k, mid + 1, high);
}
return result;
}
}
}
return -1;
}
// Handle request to find array elements
func findElement(_ arr: [Int], _ size: Int, _ k: Int)
{
let location: Int = self.binarySearch(arr, k, 0, size - 1);
if (location == -1)
{
print("\n Element ", k ," Are not exist ", terminator: "");
}
else
{
print("\n Element ", k ," exist in location ", location, terminator: "");
}
}
}
func main()
{
let task: SearchElement = SearchElement();
// Defining sorted and rotated array of integer element
let arr1: [Int] = [7, 8, 9, 1, 2, 3, 4, 5, 6];
let arr2: [Int] = [11, 22, 43, 45, 51, 62, 73, 1, 9, 10];
// Get the size
var size: Int = arr1.count;
task.display(arr1, size);
// Test Cases
task.findElement(arr1, size, 9);
task.findElement(arr1, size, 3);
// Get the size
size = arr2.count;
task.display(arr2, size);
// Test Cases
task.findElement(arr2, size, 9);
task.findElement(arr2, size, 11);
task.findElement(arr2, size, 67);
}
main();Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not exist/*
Kotlin program
Find an element in a sorted and rotated array
*/
class SearchElement
{
// Display array elements
fun display(arr: Array<Int>, size: Int): Unit
{
print("\n\n Array Elements \n [");
var i: Int = 0;
while (i<size)
{
print(" " + arr[i]);
i += 1;
}
print(" ]");
}
// Finding the element location of sorted rotated array
fun binarySearch(arr: Array<Int>, k: Int, low: Int, high: Int): Int
{
if (low>high)
{
return -1;
}
else
{
var mid: Int = (low + high) / 2;
if (arr[mid] == k)
{
// When element exist
return mid;
}
if (arr[low]<arr[mid])
{
// When elements are sort in location low to mid position
if (k>= arr[low] && k<arr[mid])
{
// When the element is possible in the (low) to (mid-1) position
return this.binarySearch(arr, k, low, mid - 1);
}
else
{
// When the element is possible in the (mid+1) to (high) position
return this.binarySearch(arr, k, mid + 1, high);
}
}
else
if (arr[mid]<arr[high])
{
if (k>arr[mid] && k <= arr[high])
{
// When the element is possible in the (mid+1) to (high) position
return this.binarySearch(arr, k, mid + 1, high);
}
else
{
// When the element is possible in the (low) to (mid-1) position
return this.binarySearch(arr, k, low, mid - 1);
}
}
else
if (arr[low] == arr[mid])
{
// When repeated array element exists
if (arr[mid] != arr[high])
{
return this.binarySearch(arr, k, mid + 1, high);
}
else
{
// Check if that element exists in left subtree
var result: Int = this.binarySearch(arr, k, low, mid - 1);
if (result == -1)
{
// When element not exist in left subtree then
// Check that element exists in right subtree
result = this.binarySearch(arr, k, mid + 1, high);
}
return result;
}
}
}
return -1;
}
// Handle request to find array elements
fun findElement(arr: Array<Int>, size: Int, k: Int): Unit
{
var location: Int = this.binarySearch(arr, k, 0, size - 1);
if (location == -1)
{
print("\n Element " + k + " Are not exist ");
}
else
{
print("\n Element " + k + " exist in location " + location);
}
}
}
fun main(args: Array<String>): Unit
{
var task: SearchElement = SearchElement();
// Defining sorted and rotated array of integer element
var arr1: Array<Int> = arrayOf(7, 8, 9, 1, 2, 3, 4, 5, 6);
var arr2: Array<Int> = arrayOf(11, 22, 43, 45, 51, 62, 73, 1, 9, 10);
// Get the size
var size: Int = arr1.count();
task.display(arr1, size);
// Test Cases
task.findElement(arr1, size, 9);
task.findElement(arr1, size, 3);
// Get the size
size = arr2.count();
task.display(arr2, size);
// Test Cases
task.findElement(arr2, size, 9);
task.findElement(arr2, size, 11);
task.findElement(arr2, size, 67);
}Output
Array Elements
[ 7 8 9 1 2 3 4 5 6 ]
Element 9 exist in location 2
Element 3 exist in location 5
Array Elements
[ 11 22 43 45 51 62 73 1 9 10 ]
Element 9 exist in location 8
Element 11 exist in location 0
Element 67 Are not existResultant Output Explanation
The given C program applies the binary search algorithm on two example arrays, arr1 and
arr2, and finds specific target elements. It then displays the results.
In the output, for arr1, the algorithm successfully finds elements 9 and 3 at indices 2 and 5,
respectively. For arr2, the algorithm finds elements 9 and 11 at indices 8 and 0, respectively, while
element 67 is not present in the array.
Time Complexity
The time complexity of the binary search algorithm in the given code is O(log n) since it reduces the search space by half in each recursive call. The algorithm performs binary search recursively on the left or right half of the array based on the comparisons, making it efficient for sorted and rotated arrays.
In conclusion, the given algorithm effectively solves the problem of finding an element in a sorted and rotated array using a modified binary search approach. It has a time complexity of O(log n) and can efficiently handle arrays with repeated elements.
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