题目:

异或运算:
相同为0,不同为1
即:
0 ^ 0 = 0 ,
0 ^ 1 = 1,
1 ^ 0 = 1 ,
1 ^ 1 = 0 ,
直接解法:
            
            
              java
              
              
            
          
          class Solution {
    public int xorOperation(int n, int start) {
        int result = 0;
        for(int i = 0;i<n;i++)
        {
            int num = start + 2*i;
            result ^=num;
        }
        return result;
    }
}降低时间复杂度


            
            
              java
              
              
            
          
          class Solution {
    public int xorOperation(int n, int start) {
        int s = start >> 1, e = n & start & 1;
        int ret = sumXor(s - 1) ^ sumXor(s + n - 1);
        return ret << 1 | e;
    }
    public int sumXor(int x) {
        if (x % 4 == 0) {
            return x;
        }
        if (x % 4 == 1) {
            return 1;
        }
        if (x % 4 == 2) {
            return x + 1;
        }
        return 0;
    }
}
作者:力扣官方题解
链接:https://leetcode.cn/problems/xor-operation-in-an-array/solutions/371258/shu-zu-yi-huo-cao-zuo-by-leetcode-solution/
来源:力扣(LeetCode)
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