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Code Array

# Find the two duplicate elements in array

Given an array of numbers (integer values), Our goal is to find the first two duplicate element which is repeating in this array. For example

``````Example 1
arr[] = {1,7,2,4,4,4,3,6,4,3 }
o/p : 4  3
Example 2
arr[] = {1,1,1,4,3,3,3,3,4,3 }
o/p : 1  4
``````

Here given code implementation process.

``````// C Program
// Find the two duplicate elements in array
#include <stdio.h>

//Function which is display array elements
void display(int arr[], int size)
{
for (int i = 0; i < size; ++i)
{
printf("%d   ", arr[i]);
}
}
// Find two repeated elements of array
void findDuplicate(int arr[], int size)
{
if (size <= 0)
{
return;
}
display(arr, size);
// Loop controlling variable
int i = 0;
int j = 0;
int result = 0;
int counter = 0;
//
int a = -1;
int b = -1;
for (i = 0; i < size - 1 && result < 2; ++i)
{
for (j = 0; j < size && counter >= 0 && counter < 2; ++j)
{
if (arr[i] == arr[j])
{
if (j < i)
{
// If element has been already tested
counter = -1;
}
else
{
counter++;
}
}
}
if (counter >= 2)
{
result++;
if (a == -1)
{
a = i;
}
else if (b == -1)
{
b = i;
}
}
counter = 0;
}
if (result == 0)
{
printf("\nNo duplicate elements exists ");
}
else
{
if (a != -1)
{
printf("\nFirst repeated : %d", arr[a]);
}
if (b != -1)
{
printf("\nSecond repeated : %d", arr[b]);
}
else
{
printf("\nSecond repeated : None");
}
}
printf("\n\n");
}
int main()
{
//Define array elements
int arr1[] = {
1 , 4 , 7 , 7 , 7 , 9 , 11 , 5 , 8 , 5
};
int size = sizeof(arr1) / sizeof(arr1[0]);
findDuplicate(arr1, size);
//Define array elements
int arr2[] = {
1 , 1 , 1 , 6 , 9 , 0 , 8 , 8 , 0 , 2 , 5 , 7 , 2 , 4 , 9
};
size = sizeof(arr2) / sizeof(arr2[0]);
findDuplicate(arr2, size);
return 0;
}``````

#### Output

``````1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9
``````
``````/*
Java Program
Find the two duplicate elements in array
*/
public class DuplicateElement
{
//Function which is display array elements
public void display(int[] arr, int size)
{
for (int i = 0; i < size; ++i)
{
System.out.print("   " + arr[i]);
}
}
// Find two repeated elements of array
public void findDuplicate(int[] arr, int size)
{
if (size <= 0)
{
return;
}
display(arr, size);
// Loop controlling variables
int i = 0;
int j = 0;
// Counter variables
int result = 0;
int counter = 0;
// Resultant variabless
int a = -1;
int b = -1;
for (i = 0; i < size - 1 && result < 2; ++i)
{
for (j = 0; j < size && counter >= 0 && counter < 2; ++j)
{
if (arr[i] == arr[j])
{
if (j < i)
{
// If element has been already tested
counter = -1;
}
else
{
counter++;
}
}
}
if (counter >= 2)
{
result++;
if (a == -1)
{
a = i;
}
else if (b == -1)
{
b = i;
}
}
counter = 0;
}
if (result == 0)
{
System.out.print("\n    No duplicate elements exists ");
}
else
{
if (a != -1)
{
System.out.print("\n    First repeated : " + arr[a] );
}
if (b != -1)
{
System.out.print("\n    Second repeated : " + arr[b]);
}
else
{
System.out.print("\n    Second repeated : None");
}
}
System.out.print("\n\n");
}
public static void main(String[] args)
{
DuplicateElement obj = new DuplicateElement();
//Define array elements
int[] arr1 = {
1 , 4 , 7 , 7 , 7 , 9 , 11 , 5 , 8 , 5
};
int size = arr1.length;
obj.findDuplicate(arr1, size);
//Define array elements
int[] arr2 = {
1 , 1 , 1 , 6 , 9 , 0 , 8 , 8 , 0 , 2 , 5 , 7 , 2 , 4 , 9
};
size = arr2.length;
obj.findDuplicate(arr2, size);
}
}``````

#### Output

``````   1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9
``````
``````// Include header file
#include <iostream>
using namespace std;

/*
C++ Program
Find the two duplicate elements in array
*/

class DuplicateElement
{
public:
//Function which is display array elements
void display(int arr[], int size)
{
for (int i = 0; i < size; ++i)
{
cout << "   " << arr[i];
}
}
// Find two repeated elements of array
void findDuplicate(int arr[], int size)
{
if (size <= 0)
{
return;
}
this->display(arr, size);
// Loop controlling variables
int i = 0;
int j = 0;
// Counter variables
int result = 0;
int counter = 0;
// Resultant variabless
int a = -1;
int b = -1;
for (i = 0; i < size - 1 && result < 2; ++i)
{
for (j = 0; j < size && counter >= 0 && counter < 2; ++j)
{
if (arr[i] == arr[j])
{
if (j < i)
{
// If element has been already tested
counter = -1;
}
else
{
counter++;
}
}
}
if (counter >= 2)
{
result++;
if (a == -1)
{
a = i;
}
else if (b == -1)
{
b = i;
}
}
counter = 0;
}
if (result == 0)
{
cout << "\n   No duplicate elements exists ";
}
else
{
if (a != -1)
{
cout << "\n   First repeated : " << arr[a];
}
if (b != -1)
{
cout << "\n   Second repeated : " << arr[b];
}
else
{
cout << "\n   Second repeated : None";
}
}
cout << "\n\n";
}
};
int main()
{
DuplicateElement obj = DuplicateElement();
//Define array elements
int arr1[] = {
1 , 4 , 7 , 7 , 7 , 9 , 11 , 5 , 8 , 5
};
int size = sizeof(arr1) / sizeof(arr1[0]);
obj.findDuplicate(arr1, size);
//Define array elements
int arr2[] = {
1 , 1 , 1 , 6 , 9 , 0 , 8 , 8 , 0 , 2 , 5 , 7 , 2 , 4 , 9
};
size = sizeof(arr2) / sizeof(arr2[0]);
obj.findDuplicate(arr2, size);
return 0;
}``````

#### Output

``````   1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9
``````
``````// Include namespace system
using System;
/*
C# Program
Find the two duplicate elements in array
*/
public class DuplicateElement
{
//Function which is display array elements
public void display(int[] arr, int size)
{
for (int i = 0; i < size; ++i)
{
Console.Write("   " + arr[i]);
}
}
// Find two repeated elements of array
public void findDuplicate(int[] arr, int size)
{
if (size <= 0)
{
return;
}
display(arr, size);
// Loop controlling variables
int i = 0;
int j = 0;
// Counter variables
int result = 0;
int counter = 0;
// Resultant variabless
int a = -1;
int b = -1;
for (i = 0; i < size - 1 && result < 2; ++i)
{
for (j = 0; j < size && counter >= 0 && counter < 2; ++j)
{
if (arr[i] == arr[j])
{
if (j < i)
{
// If element has been already tested
counter = -1;
}
else
{
counter++;
}
}
}
if (counter >= 2)
{
result++;
if (a == -1)
{
a = i;
}
else if (b == -1)
{
b = i;
}
}
counter = 0;
}
if (result == 0)
{
Console.Write("\n   No duplicate elements exists ");
}
else
{
if (a != -1)
{
Console.Write("\n   First repeated : " + arr[a]);
}
if (b != -1)
{
Console.Write("\n   Second repeated : " + arr[b]);
}
else
{
Console.Write("\n   Second repeated : None");
}
}
Console.Write("\n\n");
}
public static void Main(String[] args)
{
DuplicateElement obj = new DuplicateElement();
//Define array elements
int[] arr1 = {
1 , 4 , 7 , 7 , 7 , 9 , 11 , 5 , 8 , 5
};
int size = arr1.Length;
obj.findDuplicate(arr1, size);
//Define array elements
int[] arr2 = {
1 , 1 , 1 , 6 , 9 , 0 , 8 , 8 , 0 , 2 , 5 , 7 , 2 , 4 , 9
};
size = arr2.Length;
obj.findDuplicate(arr2, size);
}
}``````

#### Output

``````   1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9
``````
``````<?php
/*
Php Program
Find the two duplicate elements in array
*/
class DuplicateElement
{
//Function which is display array elements
public  function display( & \$arr, \$size)
{
for (\$i = 0; \$i < \$size; ++\$i)
{
echo "   ". \$arr[\$i];
}
}
// Find two repeated elements of array
public  function findDuplicate( & \$arr, \$size)
{
if (\$size <= 0)
{
return;
}
\$this->display(\$arr, \$size);
// Loop controlling variables
\$i = 0;
\$j = 0;
// Counter variables
\$result = 0;
\$counter = 0;
// Resultant variabless
\$a = -1;
\$b = -1;
for (\$i = 0; \$i < \$size - 1 && \$result < 2; ++\$i)
{
for (\$j = 0; \$j < \$size && \$counter >= 0 && \$counter < 2; ++\$j)
{
if (\$arr[\$i] == \$arr[\$j])
{
if (\$j < \$i)
{
// If element has been already tested
\$counter = -1;
}
else
{
\$counter++;
}
}
}
if (\$counter >= 2)
{
\$result++;
if (\$a == -1)
{
\$a = \$i;
}
else if (\$b == -1)
{
\$b = \$i;
}
}
\$counter = 0;
}
if (\$result == 0)
{
echo "\n    No duplicate elements exists ";
}
else
{
if (\$a != -1)
{
echo "\n    First repeated : ". \$arr[\$a];
}
if (\$b != -1)
{
echo "\n    Second repeated : ". \$arr[\$b];
}
else
{
echo "\n    Second repeated : None";
}
}
echo "\n\n";
}
}

function main()
{
\$obj = new DuplicateElement();
//Define array elements
\$arr1 = array(1, 4, 7, 7, 7, 9, 11, 5, 8, 5);
\$size = count(\$arr1);
\$obj->findDuplicate(\$arr1, \$size);
//Define array elements
\$arr2 = array(1, 1, 1, 6, 9, 0, 8, 8, 0, 2, 5, 7, 2, 4, 9);
\$size = count(\$arr2);
\$obj->findDuplicate(\$arr2, \$size);
}
main();``````

#### Output

``````   1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9
``````
``````/*
Node Js Program
Find the two duplicate elements in array
*/
class DuplicateElement
{
//Function which is display array elements
display(arr, size)
{
for (var i = 0; i < size; ++i)
{
process.stdout.write("   " + arr[i]);
}
}
// Find two repeated elements of array
findDuplicate(arr, size)
{
if (size <= 0)
{
return;
}
this.display(arr, size);
// Loop controlling variables
var i = 0;
var j = 0;
// Counter variables
var result = 0;
var counter = 0;
// Resultant variabless
var a = -1;
var b = -1;
for (i = 0; i < size - 1 && result < 2; ++i)
{
for (j = 0; j < size && counter >= 0 && counter < 2; ++j)
{
if (arr[i] == arr[j])
{
if (j < i)
{
// If element has been already tested
counter = -1;
}
else
{
counter++;
}
}
}
if (counter >= 2)
{
result++;
if (a == -1)
{
a = i;
}
else if (b == -1)
{
b = i;
}
}
counter = 0;
}
if (result == 0)
{
process.stdout.write("\n    No duplicate elements exists ");
}
else
{
if (a != -1)
{
process.stdout.write("\n    First repeated : " + arr[a]);
}
if (b != -1)
{
process.stdout.write("\n    Second repeated : " + arr[b]);
}
else
{
process.stdout.write("\n    Second repeated : None");
}
}
process.stdout.write("\n\n");
}
}

function main()
{
var obj = new DuplicateElement();
//Define array elements
var arr1 = [1, 4, 7, 7, 7, 9, 11, 5, 8, 5];
var size = arr1.length;
obj.findDuplicate(arr1, size);
//Define array elements
var arr2 = [1, 1, 1, 6, 9, 0, 8, 8, 0, 2, 5, 7, 2, 4, 9];
size = arr2.length;
obj.findDuplicate(arr2, size);
}
main();``````

#### Output

``````   1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9
``````
``````#   Python 3 Program
#   Find the two duplicate elements in array

class DuplicateElement :
# Function which is display array elements
def display(self, arr, size) :
i = 0
while (i < size) :
print("   ", arr[i], end = "")
i += 1

#  Find two repeated elements of array
def findDuplicate(self, arr, size) :
if (size <= 0) :
return

self.display(arr, size)
#  Loop controlling variables
i = 0
j = 0
#  Counter variables
result = 0
counter = 0
#  Resultant variabless
a = -1
b = -1
i = 0
while (i < size - 1 and result < 2) :
j = 0
while (j < size and counter >= 0 and counter < 2) :
if (arr[i] == arr[j]) :
if (j < i) :
#  If element has been already tested
counter = -1
else :
counter += 1

j += 1

if (counter >= 2) :
result += 1
if (a == -1) :
a = i

elif(b == -1) :
b = i

counter = 0
i += 1

if (result == 0) :
print("\n   No duplicate elements exists ", end = "")
else :
if (a != -1) :
print("\n   First repeated : ", arr[a], end = "")

if (b != -1) :
print("\n   Second repeated : ", arr[b], end = "")
else :
print("\n   Second repeated : None", end = "")

print("\n")

def main() :
obj = DuplicateElement()
# Define array elements
arr1 = [1, 4, 7, 7, 7, 9, 11, 5, 8, 5]
size = len(arr1)
obj.findDuplicate(arr1, size)
# Define array elements
arr2 = [1, 1, 1, 6, 9, 0, 8, 8, 0, 2, 5, 7, 2, 4, 9]
size = len(arr2)
obj.findDuplicate(arr2, size)

if __name__ == "__main__": main()``````

#### Output

``````    1    4    7    7    7    9    11    5    8    5
First repeated :  7
Second repeated :  5

1    1    1    6    9    0    8    8    0    2    5    7    2    4    9
First repeated :  1
Second repeated :  9
``````
``````#   Ruby Program
#   Find the two duplicate elements in array

class DuplicateElement
# Function which is display array elements
def display(arr, size)
i = 0
while (i < size)
print("   ", arr[i])
i += 1
end
end

#  Find two repeated elements of array
def findDuplicate(arr, size)
if (size <= 0)
return
end

self.display(arr, size)
#  Loop controlling variables
i = 0
j = 0
#  Counter variables
result = 0
counter = 0
#  Resultant variabless
a = -1
b = -1
i = 0
while (i < size - 1 && result < 2)
j = 0
while (j < size && counter >= 0 && counter < 2)
if (arr[i] == arr[j])
if (j < i)
#  If element has been already tested
counter = -1
else
counter += 1
end

end

j += 1
end

if (counter >= 2)
result += 1
if (a == -1)
a = i
elsif(b == -1)
b = i
end

end

counter = 0
i += 1
end

if (result == 0)
print("\n   No duplicate elements exists ")
else
if (a != -1)
print("\n   First repeated : ", arr[a])
end

if (b != -1)
print("\n   Second repeated : ", arr[b])
else
print("\n   Second repeated : None")
end

end

print("\n\n")
end

end

def main()
obj = DuplicateElement.new()
# Define array elements
arr1 = [1, 4, 7, 7, 7, 9, 11, 5, 8, 5]
size = arr1.length
obj.findDuplicate(arr1, size)
# Define array elements
arr2 = [1, 1, 1, 6, 9, 0, 8, 8, 0, 2, 5, 7, 2, 4, 9]
size = arr2.length
obj.findDuplicate(arr2, size)
end

main()``````

#### Output

``````   1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9

``````
``````/*
Scala Program
Find the two duplicate elements in array
*/
class DuplicateElement
{
//Function which is display array elements
def display(arr: Array[Int], size: Int): Unit = {
var i: Int = 0;
while (i < size)
{
print("   " + arr(i));
i += 1;
}
}
// Find two repeated elements of array
def findDuplicate(arr: Array[Int], size: Int): Unit = {
if (size <= 0)
{
return;
}
this.display(arr, size);
// Loop controlling variables
var i: Int = 0;
var j: Int = 0;
// Counter variables
var result: Int = 0;
var counter: Int = 0;
// Resultant variabless
var a: Int = -1;
var b: Int = -1;
i = 0;
while (i < size - 1 && result < 2)
{
j = 0;
while (j < size && counter >= 0 && counter < 2)
{
if (arr(i) == arr(j))
{
if (j < i)
{
// If element has been already tested
counter = -1;
}
else
{
counter += 1;
}
}
j += 1;
}
if (counter >= 2)
{
result += 1;
if (a == -1)
{
a = i;
}
else if (b == -1)
{
b = i;
}
}
counter = 0;
i += 1;
}
if (result == 0)
{
print("\n   No duplicate elements exists ");
}
else
{
if (a != -1)
{
print("\n   First repeated : " + arr(a));
}
if (b != -1)
{
print("\n   Second repeated : " + arr(b));
}
else
{
print("\n   Second repeated : None");
}
}
print("\n\n");
}
}
object Main
{
def main(args: Array[String]): Unit = {
var obj: DuplicateElement = new DuplicateElement();
//Define array elements
var arr1: Array[Int] = Array(1, 4, 7, 7, 7, 9, 11, 5, 8, 5);
var size: Int = arr1.length;
obj.findDuplicate(arr1, size);
//Define array elements
var arr2: Array[Int] = Array(1, 1, 1, 6, 9, 0, 8, 8, 0, 2, 5, 7, 2, 4, 9);
size = arr2.length;
obj.findDuplicate(arr2, size);
}
}``````

#### Output

``````   1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9
``````
``````/*
Swift 4 Program
Find the two duplicate elements in array
*/
class DuplicateElement
{
//Function which is display array elements
func display(_ arr: [Int], _ size: Int)
{
var i: Int = 0;
while (i < size)
{
print("   ", arr[i], terminator: "");
i += 1;
}
}
// Find two repeated elements of array
func findDuplicate(_ arr: [Int], _ size: Int)
{
if (size <= 0)
{
return;
}
self.display(arr, size);
// Loop controlling variables
var i: Int = 0;
var j: Int = 0;
// Counter variables
var result: Int = 0;
var counter: Int = 0;
// Resultant variabless
var a: Int = -1;
var b: Int = -1;
while (i < size - 1 && result < 2)
{
j = 0;
while (j < size && counter >= 0 && counter < 2)
{
if (arr[i] == arr[j])
{
if (j < i)
{
// If element has been already tested
counter = -1;
}
else
{
counter += 1;
}
}
j += 1;
}
if (counter >= 2)
{
result += 1;
if (a == -1)
{
a = i;
}
else if (b == -1)
{
b = i;
}
}
counter = 0;
i += 1;
}
if (result == 0)
{
print("\n  No duplicate elements exists ",terminator: "");
}
else
{
if (a != -1)
{
print("\n   First repeated : ", arr[a], terminator: "");
}
if (b != -1)
{
print("\n   Second repeated : ", arr[b], terminator: "");
}
else
{
print("\n   Second repeated : None", terminator: "");
}
}
print("\n");
}
}
func main()
{
let obj: DuplicateElement = DuplicateElement();
//Define array elements
let arr1: [Int] = [1, 4, 7, 7, 7, 9, 11, 5, 8, 5];
var size: Int = arr1.count;
obj.findDuplicate(arr1, size);
//Define array elements
let arr2: [Int] = [1, 1, 1, 6, 9, 0, 8, 8, 0, 2, 5, 7, 2, 4, 9];
size = arr2.count;
obj.findDuplicate(arr2, size);
}
main();``````

#### Output

``````    1    4    7    7    7    9    11    5    8    5
First repeated :  7
Second repeated :  5

1    1    1    6    9    0    8    8    0    2    5    7    2    4    9
First repeated :  1
Second repeated :  9
``````
``````/*
Kotlin Program
Find the two duplicate elements in array
*/
class DuplicateElement
{
//Function which is display array elements
fun display(arr: Array<Int>, size: Int): Unit
{
var i: Int = 0;
while (i<size)
{
print("   " + arr[i]);
i += 1;
}
}
// Find two repeated elements of array
fun findDuplicate(arr: Array<Int>, size: Int): Unit
{
if (size <= 0)
{
return;
}
this.display(arr, size);
// Loop controlling variables
var i: Int = 0;
var j: Int ;
// Counter variables
var result: Int = 0;
var counter: Int = 0;
// Resultant variabless
var a: Int = -1;
var b: Int = -1;
while (i<size - 1 && result<2)
{
j = 0;
while (j<size && counter>= 0 && counter<2)
{
if (arr[i] == arr[j])
{
if (j<i)
{
// If element has been already tested
counter = -1;
}
else
{
counter += 1;
}
}
j += 1;
}
if (counter>= 2)
{
result += 1;
if (a == -1)
{
a = i;
}
else
if (b == -1)
{
b = i;
}
}
counter = 0;
i += 1;
}
if (result == 0)
{
print("\n   No duplicate elements exists ");
}
else
{
if (a != -1)
{
print("\n   First repeated : " + arr[a]);
}
if (b != -1)
{
print("\n   Second repeated : " + arr[b]);
}
else
{
print("\n   Second repeated : None");
}
}
print("\n\n");
}
}
fun main(args: Array<String>): Unit
{
var obj: DuplicateElement = DuplicateElement();
//Define array elements
var arr1: Array<Int> = arrayOf(1, 4, 7, 7, 7, 9, 11, 5, 8, 5);
var size: Int = arr1.count();
obj.findDuplicate(arr1, size);
//Define array elements
var arr2: Array<Int> = arrayOf(1, 1, 1, 6, 9, 0, 8, 8, 0, 2, 5, 7, 2, 4, 9);
size = arr2.count();
obj.findDuplicate(arr2, size);
}``````

#### Output

``````   1   4   7   7   7   9   11   5   8   5
First repeated : 7
Second repeated : 5

1   1   1   6   9   0   8   8   0   2   5   7   2   4   9
First repeated : 1
Second repeated : 9
``````

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