• Question
• Solution

Question

Given an array of integers, every element appears twice except for one. Find that single one.

Note:

Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

Solution

Result: Accepted Time: 8 ms

Here should be some explanations.

int singleNumber(int* nums, int numsSize) {
    int ans = 0;
    for(int i = 0; i < numsSize; i++)
        ans ^= nums[i];
    return ans;
}

Complexity Analytics

• Time Complexity: $O(n)$
• Space Complexity: $O(1)$