136. Single Number.md

136. Single Number

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Given a non-empty 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?

Example 1:

Input: [2,2,1]
Output: 1

Example 2:

Input: [4,1,2,1,2]
Output: 4

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Solution

• mine

  • Java

    Runtime: 0 ms, faster than 100.00%, Memory Usage: 40.4 MB, less than 91.11% of Java online submissions

    //O(N)time O(1)space
    public int singleNumber(int[] nums) {
        int res = 0;
        for(int num : nums){
            res ^= num;
        }
        return res;
    }