并查集模板+二进制中1的位数mask

    int FindFather(vector<int>& nums, int father) {
        if (father == nums[father]) return father;
        return nums[father] = FindFather(nums, nums[father]);
    }

    void Init(vector<int>& nums, int n) {
        for (int i = 0; i < n; ++i)
            nums.push_back(i);
    }

    void Merge(vector<int>& nums, int x, int y) {
        int fx = FindFather(nums, x);
        int fy = FindFather(nums, y);

        if (fx != fy)
            nums[fx] = nums[fy];
    }

 

二进制如下则会求出j从最高位开始的所有可能mask

for (int s = j; s > 0; s = (s - 1) & j)

假设j=1101, 则可能的有 1101、1100、1001、1000、101、100、001