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?

题目

给出2*n + 1 个的数字，除其中一个数字之外其他每个数字均出现两次，找到这个数字。

样例
给出** [1,2,2,1,3,4,3]**，返回 4

分析

显然用异或就行了，因为其他的数均出现两次

代码

public class Solution {
    /**
      *@param A : an integer array
      *return : a integer 
      */
    public class Solution {
    public int singleNumber(int[] nums) {
    int ans =0;
    
    int len = nums.length;
    for(int i=0;i!=len;i++)
        ans ^= nums[i];
    
    return ans;
    
}
}
}

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