Given an array of N positive elements. The task is to find an element which is equal to the sum of all elements of array except itself.
Examples:
Input: arr[] = {1, 2, 3, 6} Output: 6 6 is the element which is equal to the sum of all remaining elements i.e. 1 + 2+ 3 = 6 Input: arr[] = {2, 2, 2, 2} Output: -1
Approach: First of all, find the sum of all elements of an array. Then iterate over each element and check the condition that if (a[i] == sum-a[i] ). If true then print that a[i], else print “-1” if no such element is found.
Below is the implementation of the above approach:
C++
// C++ implementation of the above approach #include <bits/stdc++.h> #define ll long long int using namespace std; // Function to find the element int findEle( int arr[], int n) { // sum is use to store // sum of all elements // of array ll sum = 0; for ( int i = 0; i < n; i++) sum += arr[i]; // iterate over all elements for ( int i = 0; i < n; i++) if (arr[i] == sum - arr[i]) return arr[i]; return -1; } // Driver code int main() { int arr[] = { 1, 2, 3, 6 }; int n = sizeof (arr) / sizeof (arr[0]); cout << findEle(arr, n); return 0; } |
Java
// Java implementation of the above approach import java.io.*; class GFG { // Function to find the element static int findEle( int arr[], int n) { // sum is use to store // sum of all elements // of array int sum = 0 ; for ( int i = 0 ; i < n; i++) sum += arr[i]; // iterate over all elements for ( int i = 0 ; i < n; i++) if (arr[i] == sum - arr[i]) return arr[i]; return - 1 ; } // Driver code public static void main (String[] args) { int arr[] = { 1 , 2 , 3 , 6 }; int n = arr.length; System.out.print(findEle(arr, n)); } } // This code is contributed by shs.. |
Python3
# Python 3 implementation of # the above approach # Function to find the element def findEle(arr, n) : # sum is use to store # sum of all elements # of array sum = 0 for i in range (n) : sum + = arr[i] # iterate over all elements for i in range (n) : if arr[i] = = sum - arr[i] : return arr[i] return - 1 # Driver Code if __name__ = = "__main__" : arr = [ 1 , 2 , 3 , 6 ] n = len (arr) print (findEle(arr, n)) # This code is contributed by Ryuga |
C#
// C# implementation of the // above approach using System; class GFG { // Function to find the element static int findEle( int []arr, int n) { // sum is use to store // sum of all elements // of array int sum = 0; for ( int i = 0; i < n; i++) sum += arr[i]; // iterate over all elements for ( int i = 0; i < n; i++) if (arr[i] == sum - arr[i]) return arr[i]; return -1; } // Driver code static public void Main (String []args) { int []arr = { 1, 2, 3, 6 }; int n = arr.Length; Console.WriteLine(findEle(arr, n)); } } // This code is contributed // by Arnab Kundu |
PHP
<?php // PHP implementation of the above approach // Function to find the element function findEle( $arr , $n ) { // sum is use to store // sum of all elements // of array $sum = 0; for ( $i = 0; $i < $n ; $i ++) $sum += $arr [ $i ]; // iterate over all elements for ( $i = 0; $i < $n ; $i ++) if ( $arr [ $i ] == $sum - $arr [ $i ]) return $arr [ $i ]; return -1; } // Driver code $arr = array (1, 2, 3, 6 ); $n = sizeof( $arr ); echo findEle( $arr , $n ); // This code is contributed // by Akanksha Rai ?> |
Javascript
<script> // javascript implementation of the above approach // Function to find the element function findEle(arr, n) { // sum is use to store // sum of all elements // of array var sum = 0; for ( var i = 0; i < n; i++) sum += arr[i]; // iterate over all elements for ( var i = 0; i < n; i++) if (arr[i] == sum - arr[i]) return arr[i]; return -1; } // Driver code var arr = [1, 2, 3, 6]; var n = arr.length; document.write(findEle(arr, n)); // This code is contributed by ipg016107. </script> |
6
Complexity Analysis:
- Time Complexity: O(n)
- Auxiliary Space: O(1)
Note: Above problem can be solved with the concept used in Check if the array has an element which is equal to sum of all the remaining elements.
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