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// 137. Single Number II
#include <stdio.h>
/*
* given an integer array 'nums' where every element appears three times except
* for one, which appears exactly once. find the single element and return it.
* you must implement a solution with a linear runtime complexity and use only
* constant extra space.
*/
int singleNumber(int *nums, int nums_size) {
int ans = 0, sum;
for (int i = 0; i < 32; i++) {
long long mask = 1 << i;
sum = 0;
for (int j = 0; j < nums_size; j++)
if (mask & nums[j])
sum++;
if (sum % 3)
ans |= mask;
}
return ans;
}
int main() {
int n1[] = {2, 2, 3, 2};
int n2[] = {0, 1, 0, 1, 0, 1, 99};
printf("%d\n", singleNumber(n1, 4)); // expect: 3
printf("%d\n", singleNumber(n2, 7)); // expect: 99
}
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