# Find duplicate elements in given array

Here given code implementation process.

/*
Java program for
Find duplicate elements in given array
*/
import java.util.HashMap;
public class Duplicate
{
// Display elements of given array
public void displayArray(int[] num, int n)
{
System.out.print("\n Array elements : ");
for (int i = 0; i < n; ++i)
{
System.out.print("  " + num[i]);
}
}
public void findDuplicateElement(int[] num, int n)
{
// Use to collect frequency of array elements
HashMap < Integer, Integer > frequency =
new HashMap < Integer, Integer > ();
boolean result = false;
// Count frequency of num elements
for (int i = 0; i < n; i++)
{
if (frequency.containsKey(num[i]))
{
// When key exist then put new key
frequency.put(num[i], frequency.get(num[i]) + 1);
}
else
{
frequency.put(num[i], 1);
}
}
// Display given elements
displayArray(num, n);
System.out.print("\n Duplicate : ");
// Display duplicate elements
for (int data: frequency.keySet())
{
if (frequency.get(data) > 1)
{
// When element are duplicate
System.out.print("  " + data);
result = true;
}
}
if (result == false)
{
System.out.print(" None");
}
}
public static void main(String[] args)
{
int[] num1 = {
5 , -4 , 1 , 4 , 6 , -7 , 1 , 6 , 3 , -4
};
int[] num2 = {
2 , 5 , 1 , 3 , 3 , 2
};
int[] num3 = {
9 , 3 , 5
};
// Test A
int n = num1.length;
// Test B
n = num2.length;
// Test C
n = num3.length;
}
}

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   1  -4  6
Array elements :   2  5  1  3  3  2
Duplicate :   2  3
Array elements :   9  3  5
Duplicate :  None
#include <iostream>
#include <unordered_map>

using namespace std;
class Duplicate
{
public:
// Display elements of given array
void displayArray(int num[], int n)
{
cout << "\n Array elements : ";
for (int i = 0; i < n; ++i)
{
cout << "  " << num[i];
}
}
void findDuplicateElement(int num[], int n)
{
// Use to collect frequency of array elements
unordered_map < int, int > frequency;
bool result = false;
// Count frequency of num elements
for (int i = 0; i < n; i++)
{
if (frequency.find(num[i]) != frequency.end())
{
// When key exist then put new key
frequency[num[i]] = frequency[num[i]] + 1;
}
else
{
frequency[num[i]] = 1;
}
}
// Display given elements
this->displayArray(num, n);
cout << "\n Duplicate : ";
// Display duplicate elements
for (auto &data: frequency)
{
if (data.second > 1)
{
// When element are duplicate
cout << "  " << data.first;
result = true;
}
}
if (result == false)
{
cout << " None";
}
}
};
int main()
{
int num1[] = {
5 , -4 , 1 , 4 , 6 , -7 , 1 , 6 , 3 , -4
};
int num2[] = {
2 , 5 , 1 , 3 , 3 , 2
};
int num3[] = {
9 , 3 , 5
};
// Test A
int n = sizeof(num1) / sizeof(num1[0]);
// Test B
n = sizeof(num2) / sizeof(num2[0]);
// Test C
n = sizeof(num3) / sizeof(num3[0]);
return 0;
}

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   6  -4  1
Array elements :   2  5  1  3  3  2
Duplicate :   3  2
Array elements :   9  3  5
Duplicate :  None
// Include namespace system
using System;
using System.Collections.Generic;
public class Duplicate
{
// Display elements of given array
public void displayArray(int[] num, int n)
{
Console.Write("\n Array elements : ");
for (int i = 0; i < n; ++i)
{
Console.Write("  " + num[i]);
}
}
public void findDuplicateElement(int[] num, int n)
{
// Use to collect frequency of array elements
Dictionary < int, int > frequency = new Dictionary < int, int > ();
Boolean result = false;
// Count frequency of num elements
for (int i = 0; i < n; i++)
{
if (frequency.ContainsKey(num[i]))
{
// When key exist then put new key
frequency[num[i]] = frequency[num[i]] + 1;
}
else
{
}
}
// Display given elements
this.displayArray(num, n);
Console.Write("\n Duplicate : ");
// Display duplicate elements
foreach(KeyValuePair < int, int > data in frequency)
{
if (data.Value > 1)
{
// When element are duplicate
Console.Write("  " + data.Key);
result = true;
}
}
if (result == false)
{
Console.Write(" None");
}
}
public static void Main(String[] args)
{
int[] num1 = {
5 , -4 , 1 , 4 , 6 , -7 , 1 , 6 , 3 , -4
};
int[] num2 = {
2 , 5 , 1 , 3 , 3 , 2
};
int[] num3 = {
9 , 3 , 5
};
// Test A
int n = num1.Length;
// Test B
n = num2.Length;
// Test C
n = num3.Length;
}
}

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   -4  1  6
Array elements :   2  5  1  3  3  2
Duplicate :   2  3
Array elements :   9  3  5
Duplicate :  None
package main
import "fmt"
/*
Go program for
Find duplicate elements in given array
*/

// Display elements of given array
func displayArray(num[] int, n int) {
fmt.Print("\n Array elements : ")
for i := 0 ; i < n ; i++ {
fmt.Print("  ", num[i])
}
}
func findDuplicateElement(num[] int, n int) {
// Use to collect frequency of array elements
var frequency = make(map[int] int)
var result bool = false
// Count frequency of num elements
for i := 0 ; i < n ; i++ {
if _, found := frequency[num[i]] ; found {
// When key exist then put new key
frequency[num[i]] = frequency[num[i]] + 1
} else {
frequency[num[i]] = 1
}
}
// Display given elements
displayArray(num, n)
fmt.Print("\n Duplicate : ")
// Display duplicate elements
for k, v := range frequency {
if v > 1 {
// When element are duplicate
fmt.Print("  ", k)
result = true
}
}
if result == false {
fmt.Print(" None")
}
}
func main() {

var num1 = [] int {5 , -4 , 1 , 4 , 6 , -7 , 1 , 6 , 3 , -4}
var num2 = [] int { 2 , 3 , 5 , 1 , 3 , 2}
var num3 = [] int {9 , 3 , 5}
// Test A
var n int = len(num1)
findDuplicateElement(num1, n)
// Test B
n = len(num2)
findDuplicateElement(num2, n)
// Test C
n = len(num3)
findDuplicateElement(num3, n)
}

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   1  -4  6
Array elements :   2  5  1  3  3  2
Duplicate :   2  3
Array elements :   9  3  5
Duplicate :  None
<?php
/*
Php program for
Find duplicate elements in given array
*/
class Duplicate
{
// Display elements of given array
public	function displayArray(\$num, \$n)
{
echo("\n Array elements : ");
for (\$i = 0; \$i < \$n; ++\$i)
{
echo("  ".\$num[\$i]);
}
}
public	function findDuplicateElement(\$num, \$n)
{
// Use to collect frequency of array elements
\$frequency = array();
\$result = false;
// Count frequency of num elements
for (\$i = 0; \$i < \$n; \$i++)
{
if (array_key_exists(\$num[\$i], \$frequency))
{
// When key exist then put new key
\$frequency[\$num[\$i]] = \$frequency[\$num[\$i]] + 1;
}
else
{
\$frequency[\$num[\$i]] = 1;
}
}
// Display given elements
\$this->displayArray(\$num, \$n);
echo("\n Duplicate : ");
// Display duplicate elements
foreach(\$frequency as \$key => \$value)
{
if (\$value > 1)
{
// When element are duplicate
echo("  ".\$key);
\$result = true;
}
}
if (\$result == false)
{
echo(" None");
}
}
}

function main()
{
\$num1 = array(5, -4, 1, 4, 6, -7, 1, 6, 3, -4);
\$num2 = array(2, 5, 1, 3, 3, 2);
\$num3 = array(9, 3, 5);
// Test A
\$n = count(\$num1);
// Test B
\$n = count(\$num2);
// Test C
\$n = count(\$num3);
}
main();

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   -4  1  6
Array elements :   2  5  1  3  3  2
Duplicate :   2  3
Array elements :   9  3  5
Duplicate :  None
/*
Node JS program for
Find duplicate elements in given array
*/
class Duplicate
{
// Display elements of given array
displayArray(num, n)
{
process.stdout.write("\n Array elements : ");
for (var i = 0; i < n; ++i)
{
process.stdout.write("  " + num[i]);
}
}
findDuplicateElement(num, n)
{
// Use to collect frequency of array elements
var frequency = new Map();
var result = false;
// Count frequency of num elements
for (var i = 0; i < n; i++)
{
if (frequency.has(num[i]))
{
// When key exist then put new key
frequency.set(num[i], frequency.get(num[i]) + 1);
}
else
{
frequency.set(num[i], 1);
}
}
// Display given elements
this.displayArray(num, n);
process.stdout.write("\n Duplicate : ");
// Display duplicate elements
for (let [key, value] of frequency)
{
if (value > 1)
{
// When element are duplicate
process.stdout.write("  " + key);
result = true;
}
}
if (result == false)
{
process.stdout.write(" None");
}
}
}

function main()
{
var num1 = [5, -4, 1, 4, 6, -7, 1, 6, 3, -4];
var num2 = [2, 5, 1, 3, 3, 2];
var num3 = [9, 3, 5];
// Test A
var n = num1.length;
// Test B
n = num2.length;
// Test C
n = num3.length;
}
main();

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   -4  1  6
Array elements :   2  5  1  3  3  2
Duplicate :   2  3
Array elements :   9  3  5
Duplicate :  None
#    Python 3 program for
#    Find duplicate elements in given array
class Duplicate :
#  Display elements of given list
def displayArray(self, num, n) :
print("\n Array elements : ", end = "")
i = 0
while (i < n) :
print("  ", num[i], end = "")
i += 1

def findDuplicateElement(self, num, n) :
#  Use to collect frequency of list elements
frequency = dict()
result = False
i = 0
#  Count frequency of num elements
while (i < n) :
if ((num[i] in frequency.keys())) :
#  When key exist then put new key
frequency[num[i]] = frequency.get(num[i]) + 1
else :
frequency[num[i]] = 1

i += 1

#  Display given elements
self.displayArray(num, n)
print("\n Duplicate : ", end = "")
for key, value in frequency.items() :
if (value > 1) :
#  When element are duplicate
print("  ", key, end = "")
result = True

if (result == False) :
print(" None", end = "")

def main() :
num1 = [5, -4, 1, 4, 6, -7, 1, 6, 3, -4]
num2 = [2, 5, 1, 3, 3, 2]
num3 = [9, 3, 5]
#  Test A
n = len(num1)
#  Test B
n = len(num2)
#  Test C
n = len(num3)

if __name__ == "__main__": main()

#### Output

Array elements :    5   -4   1   4   6   -7   1   6   3   -4
Duplicate :    1   6   -4
Array elements :    2   5   1   3   3   2
Duplicate :    2   3
Array elements :    9   3   5
Duplicate :  None
#    Ruby program for
#    Find duplicate elements in given array
class Duplicate
#  Display elements of given array
def displayArray(num, n)
print("\n Array elements : ")
i = 0
while (i < n)
print("  ", num[i])
i += 1
end

end

def findDuplicateElement(num, n)
#  Use to collect frequency of array elements
frequency = Hash.new()
result = false
i = 0
#  Count frequency of num elements
while (i < n)
if (frequency.key?(num[i]))
#  When key exist then put new key
frequency[num[i]] = frequency[num[i]] + 1
else

frequency[num[i]] = 1
end

i += 1
end

#  Display given elements
self.displayArray(num, n)
print("\n Duplicate : ")
#  Display duplicate elements
frequency.each { | key, value |
if (value > 1)
#  When element are duplicate
print("  ", key)
result = true
end

}
if (result == false)
print(" None")
end

end

end

def main()
num1 = [5, -4, 1, 4, 6, -7, 1, 6, 3, -4]
num2 = [2, 5, 1, 3, 3, 2]
num3 = [9, 3, 5]
#  Test A
n = num1.length
#  Test B
n = num2.length
#  Test C
n = num3.length
end

main()

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   -4  1  6
Array elements :   2  5  1  3  3  2
Duplicate :   2  3
Array elements :   9  3  5
Duplicate :  None
import scala.collection.mutable._;
/*
Scala program for
Find duplicate elements in given array
*/
class Duplicate()
{
// Display elements of given array
def displayArray(num: Array[Int], n: Int): Unit = {
print("\n Array elements : ");
var i: Int = 0;
while (i < n)
{
print("  " + num(i));
i += 1;
}
}
def findDuplicateElement(num: Array[Int], n: Int): Unit = {
// Use to collect frequency of array elements
var frequency: HashMap[Int, Int] = new HashMap[Int, Int]();
var result: Boolean = false;
var i: Int = 0;
// Count frequency of num elements
while (i < n)
{
if (frequency.contains(num(i)))
{
// When key exist then put new key
}
else
{
}
i += 1;
}
// Display given elements
displayArray(num, n);
print("\n Duplicate : ");
// Display duplicate elements
for ((key, value) <- frequency)
{
if (value > 1)
{
// When element are duplicate
print("  " + key);
result = true;
}
}
if (result == false)
{
print(" None");
}
}
}
object Main
{
def main(args: Array[String]): Unit = {
var task: Duplicate = new Duplicate();
var num1: Array[Int] = Array(5, -4, 1, 4, 6, -7, 1, 6, 3, -4);
var num2: Array[Int] = Array(2, 5, 1, 3, 3, 2);
var num3: Array[Int] = Array(9, 3, 5);
// Test A
var n: Int = num1.length;
// Test B
n = num2.length;
// Test C
n = num3.length;
}
}

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   1  -4  6
Array elements :   2  5  1  3  3  2
Duplicate :   2  3
Array elements :   9  3  5
Duplicate :  None
import Foundation;
/*
Swift 4 program for
Find duplicate elements in given array
*/
class Duplicate
{
// Display elements of given array
func displayArray(_ num: [Int], _ n: Int)
{
print("\n Array elements : ", terminator: "");
var i: Int = 0;
while (i < n)
{
print("  ", num[i], terminator: "");
i += 1;
}
}
func findDuplicateElement(_ num: [Int], _ n: Int)
{
// Use to collect frequency of array elements
var frequency = [Int: Int]();
var result: Bool = false;
var i: Int = 0;
// Count frequency of num elements
while (i < n)
{
if (frequency.keys.contains(num[i]))
{
// When key exist then put new key
frequency[num[i]] = frequency[num[i]]! + 1;
}
else
{
frequency[num[i]] = 1;
}
i += 1;
}
// Display given elements
self.displayArray(num, n);
print("\n Duplicate : ", terminator: "");
// Display duplicate elements
for (key, value) in frequency
{
if (value > 1)
{
// When element are duplicate
print("  ", key, terminator: "");
result = true;
}
}
if (result == false)
{
print(" None", terminator: "");
}
}
}
func main()
{
let num1: [Int] = [5, -4, 1, 4, 6, -7, 1, 6, 3, -4];
let num2: [Int] = [2, 5, 1, 3, 3, 2];
let num3: [Int] = [9, 3, 5];
// Test A
var n: Int = num1.count;
// Test B
n = num2.count;
// Test C
n = num3.count;
}
main();

#### Output

Array elements :    5   -4   1   4   6   -7   1   6   3   -4
Duplicate :    -4   6   1
Array elements :    2   5   1   3   3   2
Duplicate :    2   3
Array elements :    9   3   5
Duplicate :  None
/*
Kotlin program for
Find duplicate elements in given array
*/
class Duplicate
{
// Display elements of given array
fun displayArray(num: Array < Int > , n: Int): Unit
{
print("\n Array elements : ");
var i: Int = 0;
while (i < n)
{
print("  " + num[i]);
i += 1;
}
}
fun findDuplicateElement(num: Array < Int > , n: Int): Unit
{
// Use to collect frequency of array elements
val frequency = HashMap < Int , Int > ();
var result: Boolean = false;
var i: Int = 0;
// Count frequency of num elements
while (i < n)
{
if (frequency.containsKey(num[i]))
{
// When key exist then put new key
frequency.put(num[i], frequency.getValue(num[i]) + 1);
}
else
{
frequency.put(num[i], 1);
}
i += 1;
}
// Display given elements
this.displayArray(num, n);
print("\n Duplicate : ");
// Display duplicate elements
for ((key, value) in frequency)
{
if (value > 1)
{
// When element are duplicate
print("  " + key);
result = true;
}
}
if (result == false)
{
print(" None");
}
}
}
fun main(args: Array < String > ): Unit
{
val num1: Array < Int > = arrayOf(5, -4, 1, 4, 6, -7, 1, 6, 3, -4);
val num2: Array < Int > = arrayOf(2, 5, 1, 3, 3, 2);
val num3: Array < Int > = arrayOf(9, 3, 5);
// Test A
var n: Int = num1.count();
// Test B
n = num2.count();
// Test C
n = num3.count();
}

#### Output

Array elements :   5  -4  1  4  6  -7  1  6  3  -4
Duplicate :   1  -4  6
Array elements :   2  5  1  3  3  2
Duplicate :   2  3
Array elements :   9  3  5
Duplicate :  None

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