Replace every element with the greatest element on right side
Last Updated :
23 Jul, 2025
Given an array of integers, replace every element with the next greatest element (greatest element on the right side) in the array. Since there is no element next to the last element, replace it with -1. For example, if the array is {16, 17, 4, 3, 5, 2}, then it should be modified to {17, 5, 5, 5, 2, -1}.
The question is very similar to this post and solutions are also similar.
A Naive method is to run two loops. The outer loop will one by one pick array elements from left to right. The inner loop will find the greatest element present after the picked element. Finally the outer loop will replace the picked element with the greatest element found by inner loop. The time complexity of this method will be O(n*n).
C++
// THIS CODE IS CONTRIBUTED BY KIRTI AGARWAL(KIRTIAGARWAL23121999)
// C++ Program to replace every element with the greatest
// element on right side
#include <bits/stdc++.h>
using namespace std;
// Function to replace every element with the
// next greatest element
void nextGreatest(int arr[], int n){
for(int i = 0; i<n; i++){
int max_value = -1;
for(int j = i+1; j<n; j++){
max_value = max(max_value, arr[j]);
}
arr[i] = max_value;
}
}
// A utility Function that prints an array
void printArray(int arr[], int size){
for (int i = 0; i < size; i++)
cout << arr[i] << " ";
cout << endl;
}
// Driver program to test above function
int main(){
int arr[] = {16, 17, 4, 3, 5, 2};
int size = sizeof(arr)/sizeof(arr[0]);
nextGreatest (arr, size);
cout << "The modified array is: \n";
printArray (arr, size);
return (0);
}
// Java Program to replace every element with the greatest
// element on right side
class Main {
// Function to replace every element with the
// next greatest element
static void nextGreatest(int arr[], int n)
{
for (int i = 0; i < n; i++) {
int max_value = -1;
for (int j = i + 1; j < n; j++) {
max_value = Math.max(max_value, arr[j]);
}
arr[i] = max_value;
}
}
// A utility Function that prints an array
static void printArray(int arr[], int size)
{
for (int i = 0; i < size; i++)
System.out.print(arr[i] + " ");
System.out.println();
}
// Driver program to test above function
public static void main(String[] args)
{
int arr[] = { 16, 17, 4, 3, 5, 2 };
int size = arr.length;
nextGreatest(arr, size);
System.out.println("The modified array is: ");
printArray(arr, size);
}
}
# Function to replace every element with the next greatest element
def nextGreatest(arr, n):
for i in range(n):
max_value = -1
for j in range(i+1, n):
max_value = max(max_value, arr[j])
arr[i] = max_value
# A utility Function that prints an array
def printArray(arr, size):
for i in range(size):
print(arr[i], end=" ")
print()
# Driver program to test above function
if __name__ == '__main__':
arr = [16, 17, 4, 3, 5, 2]
size = len(arr)
nextGreatest(arr, size)
print("The modified array is:")
printArray(arr, size)
using System;
public class MainClass
{
// Function to replace every element with the
// next greatest element
static void NextGreatest(int[] arr, int n)
{
for (int i = 0; i < n; i++)
{
int max_value = -1;
for (int j = i + 1; j < n; j++)
{
max_value = Math.Max(max_value, arr[j]);
}
arr[i] = max_value;
}
}
// A utility Function that prints an array
static void PrintArray(int[] arr, int size)
{
for (int i = 0; i < size; i++)
{
Console.Write(arr[i] + " ");
}
Console.WriteLine();
}
// Driver program to test above function
public static void Main(string[] args)
{
int[] arr = { 16, 17, 4, 3, 5, 2 };
int size = arr.Length;
NextGreatest(arr, size);
Console.WriteLine("The modified array is: ");
PrintArray(arr, size);
}
}
// JavaScript Program to replace every element with
// the greatest element on right side
// Function to replace every element with the next greatest element
function nextGreatest(arr, n) {
for(let i = 0; i < n; i++) {
let max_value = -1;
for(let j = i + 1; j < n; j++) {
max_value = Math.max(max_value, arr[j]);
}
arr[i] = max_value;
}
}
// A utility function that prints an array
function printArray(arr, size) {
for(let i = 0; i < size; i++) {
console.log(arr[i] + " ");
}
console.log("\n");
}
// Driver program to test above function
let arr = [16, 17, 4, 3, 5, 2];
let size = arr.length;
nextGreatest(arr, size);
console.log("The modified array is: ");
printArray(arr, size);
OutputThe modified array is:
17 5 5 5 2 -1
Time Complexity: O(N^2)
Auxiliary Space: O(1)
A tricky method is to replace all elements using one traversal of the array. The idea is to start from the rightmost element, move to the left side one by one, and keep track of the maximum element. Replace every element with the maximum element.
C++
// C++ Program to replace every element with the greatest
// element on right side
#include <bits/stdc++.h>
using namespace std;
/* Function to replace every element with the
next greatest element */
void nextGreatest(int arr[], int size)
{
//Initialise maxFromRight with -1
int maxFromRight = -1;
int n = size;
// run loop from last and replace maxFromRight with the element in the array
for(int i= n-1; i>=0;i--) {
int temp = maxFromRight;
if(arr[i]> maxFromRight){
//replacing only array element with maxFromRight in case element is bigger
maxFromRight = arr[i];
}
arr[i] = temp;
}
return;
}
/* A utility Function that prints an array */
void printArray(int arr[], int size)
{
int i;
for (i = 0; i < size; i++)
cout << arr[i] << " ";
cout << endl;
}
/* Driver program to test above function */
int main()
{
int arr[] = {16, 17, 4, 3, 5, 2};
int size = sizeof(arr)/sizeof(arr[0]);
nextGreatest (arr, size);
cout << "The modified array is: \n";
printArray (arr, size);
return (0);
}
// This is code is contributed by rathbhupendra
// C Program to replace every element with the greatest
// element on right side
#include <stdio.h>
/* Function to replace every element with the
next greatest element */
void nextGreatest(int arr[], int size)
{
// Initialize the next greatest element
int max_from_right = arr[size-1];
// The next greatest element for the rightmost element
// is always -1
arr[size-1] = -1;
// Replace all other elements with the next greatest
for(int i = size-2; i >= 0; i--)
{
// Store the current element (needed later for updating
// the next greatest element)
int temp = arr[i];
// Replace current element with the next greatest
arr[i] = max_from_right;
// Update the greatest element, if needed
if(max_from_right < temp)
max_from_right = temp;
}
}
/* A utility Function that prints an array */
void printArray(int arr[], int size)
{
int i;
for (i=0; i < size; i++)
printf("%d ", arr[i]);
printf("\n");
}
/* Driver program to test above function */
int main()
{
int arr[] = {16, 17, 4, 3, 5, 2};
int size = sizeof(arr)/sizeof(arr[0]);
nextGreatest (arr, size);
printf ("The modified array is: \n");
printArray (arr, size);
return (0);
}
// Java Program to replace every element with the
// greatest element on right side
import java.io.*;
class NextGreatest
{
/* Function to replace every element with the
next greatest element */
static void nextGreatest(int arr[])
{
int size = arr.length;
// Initialize the next greatest element
int max_from_right = arr[size-1];
// The next greatest element for the rightmost
// element is always -1
arr[size-1] = -1;
// Replace all other elements with the next greatest
for (int i = size-2; i >= 0; i--)
{
// Store the current element (needed later for
// updating the next greatest element)
int temp = arr[i];
// Replace current element with the next greatest
arr[i] = max_from_right;
// Update the greatest element, if needed
if(max_from_right < temp)
max_from_right = temp;
}
}
/* A utility Function that prints an array */
static void printArray(int arr[])
{
for (int i=0; i < arr.length; i++)
System.out.print(arr[i]+" ");
}
public static void main (String[] args)
{
int arr[] = {16, 17, 4, 3, 5, 2};
nextGreatest (arr);
System.out.println("The modified array:");
printArray (arr);
}
}
/*This code is contributed by Devesh Agrawal*/
# Python Program to replace every element with the
# greatest element on right side
# Function to replace every element with the next greatest
# element
def nextGreatest(arr):
size = len(arr)
# Initialize the next greatest element
max_from_right = arr[size-1]
# The next greatest element for the rightmost element
# is always -1
arr[size-1] = -1
# Replace all other elements with the next greatest
for i in range(size-2,-1,-1):
# Store the current element (needed later for updating
# the next greatest element)
temp = arr[i]
# Replace current element with the next greatest
arr[i]=max_from_right
# Update the greatest element, if needed
if max_from_right< temp:
max_from_right=temp
# Utility function to print an array
def printArray(arr):
for i in range(0,len(arr)):
print (arr[i],end=" ")
# Driver function to test above function
arr = [16, 17, 4, 3, 5, 2]
nextGreatest(arr)
print ("Modified array is")
printArray(arr)
# This code is contributed by Devesh Agrawal
// C# Program to replace every element with the
// greatest element on right side
using System;
class GFG {
/* Function to replace every element with
the next greatest element */
static void nextGreatest(int []arr)
{
int size = arr.Length;
// Initialize the next greatest element
int max_from_right = arr[size-1];
// The next greatest element for the
// rightmost element is always -1
arr[size-1] = -1;
// Replace all other elements with the
// next greatest
for (int i = size-2; i >= 0; i--)
{
// Store the current element (needed
// later for updating the next
// greatest element)
int temp = arr[i];
// Replace current element with
// the next greatest
arr[i] = max_from_right;
// Update the greatest element, if
// needed
if(max_from_right < temp)
max_from_right = temp;
}
}
/* A utility Function that prints an array */
static void printArray(int []arr)
{
for (int i=0; i < arr.Length; i++)
Console.Write(arr[i]+" ");
}
public static void Main ()
{
int []arr = {16, 17, 4, 3, 5, 2};
nextGreatest (arr);
Console.WriteLine("The modified array:");
printArray (arr);
}
}
/* This code is contributed by vt_m.*/
<?php
// PHP Program to replace every element with
// the greatest element on right side
/* Function to replace every element
with the next greatest element */
function nextGreatest(&$arr, $size)
{
// Initialize the next greatest element
$max_from_right = $arr[$size - 1];
// The next greatest element for the
// rightmost element is always -1
$arr[$size - 1] = -1;
// Replace all other elements with
// the next greatest
for($i = $size - 2; $i >= 0; $i--)
{
// Store the current element (needed
// later for updating the next
// greatest element)
$temp = $arr[$i];
// Replace current element with the
// next greatest
$arr[$i] = $max_from_right;
// Update the greatest element,
// if needed
if($max_from_right < $temp)
$max_from_right = $temp;
}
}
// A utility Function that prints an array
function printArray($arr, $size)
{
for ($i = 0; $i < $size; $i++)
echo $arr[$i] . " ";
echo "\n";
}
// Driver Code
$arr = array(16, 17, 4, 3, 5, 2);
$size = count($arr);
nextGreatest ($arr, $size);
echo "The modified array is: \n";
printArray ($arr, $size);
// This code is contributed by
// rathbhupendra
?>
<script>
// JavaScript Program to replace every element with the greatest
// element on right side
/* Function to replace every element with the
next greatest element */
function nextGreatest(arr,size)
{
// Initialize the next greatest element
max_from_right = arr[size-1];
// The next greatest element for the rightmost element
// is always -1
arr[size-1] = -1;
// Replace all other elements with the next greatest
for(let i = size-2; i >= 0; i--)
{
// Store the current element (needed later for updating
// the next greatest element)
temp = arr[i];
// Replace current element with the next greatest
arr[i] = max_from_right;
// Update the greatest element, if needed
if(max_from_right < temp)
max_from_right = temp;
}
}
/* A utility Function that prints an array */
function printArray(arr,size)
{
var i;
for ( let i = 0; i < size; i++)
document.write(arr[i] + " " );
}
/* Driver program to test above function */
arr = new Array (16, 17, 4, 3, 5, 2);
size = arr.length;
nextGreatest (arr, size);
document.write ("The modified array is: " + "<br>"+ " \n");
printArray (arr, size);
// This code is contributed by simranarora5sos
</script>
Output:
The modified array is:
17 5 5 5 2 -1
Time Complexity: O(n) where n is the number of elements in array.
Auxiliary Space: O(1)
Please write comments if you find any of the above codes/algorithms incorrect, or find other ways to solve the same problem.
Replace every element with the greatest element on right side
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