Replace every element of the array by product of all other elements

Given an array of positive integers. Replace every element by the product of all other elements of the array.

Examples:

Input : arr[] = { 2, 3, 3, 5, 7 } 
Output : 315 210 210 126 90

Approach :

• First, take the product of all the element of the array.
• Now replace each element by the product divided by that element.
• Print the modified array.

Below is the implementation of above approach: 

C++

// C++ program to Replace every element
// by the product of all other elements
#include "iostream"
using namespace std;

void ReplaceElements(int arr[], int n)
{
    int prod = 1;

    // Calculate the product of all the elements
    for (int i = 0; i < n; ++i) {
        prod *= arr[i];
    }

    // Replace every element product
    // of all other elements
    for (int i = 0; i < n; ++i) {
        arr[i] = prod / arr[i];
    }
}

int main()
{
    int arr[] = { 2, 3, 3, 5, 7 };
    int n = sizeof(arr) / sizeof(arr[0]);

    ReplaceElements(arr, n);

    // Print the modified array.
    for (int i = 0; i < n; ++i) {
        cout << arr[i] << " ";
    }
    return 0;
}

Java

// Java program to Replace every element
// by the product of all other elements

class GFG{
static void ReplaceElements(int arr[], int n)
{
    int prod = 1;

    // Calculate the product of all the elements
    for (int i = 0; i < n; ++i) {
        prod *= arr[i];
    }

    // Replace every element product
    // of all other elements
    for (int i = 0; i < n; ++i) {
        arr[i] = prod / arr[i];
    }
}

public static void main(String[] args)
{
    int arr[] = { 2, 3, 3, 5, 7 };
    int n = arr.length;

    ReplaceElements(arr, n);

    // Print the modified array.
    for (int i = 0; i < n; ++i) {
        System.out.print(arr[i]+" ");
    }
    System.out.println("");

}
}
// This code is contributed by mits

Python 3

# Python 3 program to Replace every
# element by the product of all
# other elements

def ReplaceElements(arr, n):
    prod = 1

    # Calculate the product of
    # all the elements
    for i in range(n):
        prod *= arr[i]

    # Replace every element product
    # of all other elements
    for i in range(n) :
        arr[i] = prod // arr[i]

# Driver Code
if __name__ == "__main__":
    arr = [ 2, 3, 3, 5, 7 ]
    n = len(arr)

    ReplaceElements(arr, n)

    # Print the modified array.
    for i in range( n):
        print(arr[i], end = " ")

# This code is contributed
# by ChitraNayal

C#

// C# program to Replace every element
// by the product of all other elements
using System;

class GFG
{
static void ReplaceElements(int []arr, int n)
{
    int prod = 1;

    // Calculate the product of
    // all the elements
    for (int i = 0; i < n; ++i)
    {
        prod *= arr[i];
    }

    // Replace every element product
    // of all other elements
    for (int i = 0; i < n; ++i)
    {
        arr[i] = prod / arr[i];
    }
}

// Driver Code
static public void Main ()
{
    int []arr = { 2, 3, 3, 5, 7 };
    int n = arr.Length;

    ReplaceElements(arr, n);

    // Print the modified array.
    for (int i = 0; i < n; ++i)
    {
        Console.Write(arr[i]+" ");
    }
    Console.WriteLine("");
}
}

// This code is contributed by ajit

PHP

<?php
// PHP program to Replace every element
// by the product of all other elements

function ReplaceElements($arr, $n)
{
    $prod = 1;

    // Calculate the product of all
    // the elements
    for ($i = 0; $i < $n; ++$i)
    {
        $prod *= $arr[$i];
    }

    // Replace every element product
    // of all other elements
    for ($i = 0; $i < $n; ++$i)
    {
        $arr[$i] = (int)($prod / $arr[$i]);
    }
    return $arr;
}

// Driver Code
$arr = array( 2, 3, 3, 5, 7 );
$n = sizeof($arr);

$arr1 = ReplaceElements($arr, $n);

// Print the modified array.
for ($i = 0; $i < $n; ++$i)
{
    echo $arr1[$i] . " ";
}

// This code is contributed
// by Akanksha Rai
?>

Javascript

<script>
    // Javascript program to Replace every element
    // by the product of all other elements

    function ReplaceElements(arr, n)
    {
        let prod = 1;

        // Calculate the product of
        // all the elements
        for (let i = 0; i < n; ++i)
        {
            prod *= arr[i];
        }

        // Replace every element product
        // of all other elements
        for (let i = 0; i < n; ++i)
        {
            arr[i] = parseInt(prod / arr[i], 10);
        }
    }

    let arr = [ 2, 3, 3, 5, 7 ];
    let n = arr.length;

    ReplaceElements(arr, n);

    // Print the modified array.
    for (let i = 0; i < n; ++i)
    {
        document.write(arr[i]+" ");
    }

</script>

Output

315 210 210 126 90 

Complexity Analysis:

• Time Complexity: O(N)
• Auxiliary Space: O(1)