136. Single Number.md

136. Single Number

Solution 1

• xor

class Solution {
    public int singleNumber(int[] nums) {
        //there are two same elemets and find the unique one
        //Using xor: same elemet will be 0, different will be one
        //and further more aa^a^b  = b
        int res = 0;
        for(int num : nums){
            res ^= num;
        }
        return res;
    }
}

Solution 2

• using hahet, push unmet element and pop same elemnt, then only unique element left

Accepted

Runtime: 0 ms, faster than 100.00% of Java online submissions for Single Number.
Memory Usage: 39.2 MB, less than 81.48% of Java online submissions for Single Number.

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