Count Triplets That Can Form Two Arrays of Equal XOR（C++形成两个异或相等数组的三元组数目）

不念不忘少年蓝@ 2023-01-02 16:16 80阅读 0赞

解题思路：

（1）需要用到数学推导，参考网址：[https://leetcode.com/problems/count-triplets-that-can-form-two-arrays-of-equal-xor/discuss/623747/JavaC%2B%2BPython-One-Pass-O(N4)-to-O(N)][https_leetcode.com_problems_count-triplets-that-can-form-two-arrays-of-equal-xor_discuss_623747_JavaC_2B_2BPython-One-Pass-O_N4_-to-O_N]

class Solution {
    public:
        int countTriplets(vector<int>& arr) {
            int count=0,temp=arr[0];
            int *a = new int[arr.size()+1];
            for(int i=0;i<arr.size()+1;i++) {
                if(i==0) a[i]=0;
                else if(i==1) a[i]=arr[0];
                else {
                    temp = temp^arr[i-1];
                    a[i]=temp;
                }
            }
                 
            for(int i=0;i<arr.size()+1;i++) {
                for(int j=i+2;j<arr.size()+1;j++) {
                    if(a[i]==a[j]) 
                        count=count+j-i-1;
                }
            }
            return count;
        }
    };

[https_leetcode.com_problems_count-triplets-that-can-form-two-arrays-of-equal-xor_discuss_623747_JavaC_2B_2BPython-One-Pass-O_N4_-to-O_N]: https://leetcode.com/problems/count-triplets-that-can-form-two-arrays-of-equal-xor/discuss/623747/JavaC%2B%2BPython-One-Pass-O%28N4%29-to-O%28N%29