Construct an array from XOR of all elements of array except element at same index
Given an array A[] having n positive elements. The task to create another array B[] such as B[i] is XOR of all elements of array A[] except A[i].
Examples :
Input : A[] = {2, 1, 5, 9} Output : B[] = {13, 14, 10, 6} Input : A[] = {2, 1, 3, 6} Output : B[] = {4, 7, 5, 0}
Naive Approach :
We can simple calculate B[i] as XOR of all elements of A[] except A[i], as
for (int i = 0; i < n; i++) { B[i] = 0; for (int j = 0; j < n; j++) if ( i != j) B[i] ^= A[j]; }
Time complexity for this naive approach is O (n^2).
Auxiliary Space for this naive approach is O (n).
Optimized Approach :
First calculate XOR of all elements of array A[] say ‘xor’, and for each element of array A[] calculate A[i] = xor ^ A[i] .
int xor = 0; for (int i = 0; i < n; i++) xor ^= A[i]; for (int i = 0; i < n; i++) A[i] = xor ^ A[i];
Time complexity for this approach is O (n).
Auxiliary Space for this approach is O (1).
C++
// C++ program to construct array from // XOR of elements of given array #include <bits/stdc++.h> using namespace std; // function to construct new array void constructXOR( int A[], int n) { // calculate xor of array int XOR = 0; for ( int i = 0; i < n; i++) XOR ^= A[i]; // update array for ( int i = 0; i < n; i++) A[i] = XOR ^ A[i]; } // Driver code int main() { int A[] = { 2, 4, 1, 3, 5}; int n = sizeof (A) / sizeof (A[0]); constructXOR(A, n); // print result for ( int i = 0; i < n; i++) cout << A[i] << " " ; return 0; } |
Java
// Java program to construct array from // XOR of elements of given array class GFG { // function to construct new array static void constructXOR( int A[], int n) { // calculate xor of array int XOR = 0 ; for ( int i = 0 ; i < n; i++) XOR ^= A[i]; // update array for ( int i = 0 ; i < n; i++) A[i] = XOR ^ A[i]; } // Driver code public static void main(String[] args) { int A[] = { 2 , 4 , 1 , 3 , 5 }; int n = A.length; constructXOR(A, n); // print result for ( int i = 0 ; i < n; i++) System.out.print(A[i] + " " ); } } // This code is contributed by Anant Agarwal. |
Python3
# Python 3 program to construct # array from XOR of elements # of given array # function to construct new array def constructXOR(A, n): # calculate xor of array XOR = 0 for i in range ( 0 , n): XOR ^ = A[i] # update array for i in range ( 0 , n): A[i] = XOR ^ A[i] # Driver code A = [ 2 , 4 , 1 , 3 , 5 ] n = len (A) constructXOR(A, n) # print result for i in range ( 0 ,n): print (A[i], end = " " ) # This code is contributed by Smitha Dinesh Semwal |
C#
// C# program to construct array from // XOR of elements of given array using System; class GFG { // function to construct new array static void constructXOR( int []A, int n) { // calculate xor of array int XOR = 0; for ( int i = 0; i < n; i++) XOR ^= A[i]; // update array for ( int i = 0; i < n; i++) A[i] = XOR ^ A[i]; } // Driver code public static void Main() { int []A = { 2, 4, 1, 3, 5}; int n = A.Length; constructXOR(A, n); // print result for ( int i = 0; i < n; i++) Console.Write(A[i] + " " ); } } // This code is contributed by nitin mittal |
PHP
<?php // Program to construct array from // XOR of elements of given array // function to construct new array function constructXOR(& $A , $n ) { // calculate xor of array $XOR = 0; for ( $i = 0; $i < $n ; $i ++) $XOR ^= $A [ $i ]; // update array for ( $i = 0; $i < $n ; $i ++) $A [ $i ] = $XOR ^ $A [ $i ]; } // Driver code $A = array ( 2, 4, 1, 3, 5); $n = sizeof( $A ); constructXOR( $A , $n ); // print result for ( $i = 0; $i < $n ; $i ++) echo $A [ $i ] . " " ; // This code is contributed // by ChitraNayal ?> |
Javascript
<script> // JavaScript program to construct array from // XOR of elements of given array // function to construct new array function constructXOR(A, n) { // calculate xor of array let XOR = 0; for (let i = 0; i < n; i++) XOR ^= A[i]; // update array for (let i = 0; i < n; i++) A[i] = XOR ^ A[i]; } // Driver code let A = [ 2, 4, 1, 3, 5]; let n = A.length; constructXOR(A, n); // print result for (let i = 0; i < n; i++) document.write(A[i] + " " ); // This code is contributed by Surbhi Tyagi. </script> |
Output:
3 5 0 2 4
Related Problem :
A Product Array Puzzle
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