Find the Number Occurring Odd Number of Times | GeeksforGeeks

Given an array of positive integers. All numbers occur even number of times except one number which occurs odd number of times. Find the number in O(n) time & constant space.

Example:
I/P = [1, 2, 3, 2, 3, 1, 3]
O/P = 3

Algorithm:
Do bitwise XOR of all the elements. Finally we get the number which has odd occurrences.

Program:

#include <stdio.h>   int getOddOccurrence(int ar[], int ar_size) {      int i;      int res = 0;      for (i=0; i < ar_size; i++)             res = res ^ ar[i];             return res; }

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