leetcode 947. 移除最多的同行或同列石头

c++

class Solution {
public:
    class UnionSet {
    public:
        int *father, n;
        UnionSet(int n) : n(n) {
            father = new int[n + 1]; 
            for (int i = 0; i <= n; i++) {
                father[i] = i;
            }
        }
        int find(int x) {
            return father[x] = (father[x] == x ? x : find(father[x]));
        }
        void merge(int a, int b) {
            father[find(a)] = find(b);
            return ;
        }
    };
    int removeStones(vector<vector<int>>& stones) {
        UnionSet u(stones.size());
        unordered_map<int, int> map_x, map_y;
        for (int i = 0; i < stones.size(); i++) {
            if (map_x.find(stones[i][0]) != map_x.end()) {
                u.merge(i, map_x[stones[i][0]]);
            }
            if (map_y.find(stones[i][1]) != map_y.end()) {
                u.merge(i, map_y[stones[i][1]]);
            }
            map_x[stones[i][0]] = i;
            map_y[stones[i][1]] = i;
        }
        int cnt = 0;
        for (int i = 0; i < stones.size(); i++) {
            if (u.find(i) == i) cnt++;
        }
        return stones.size() - cnt;
    }
};

js

class UnionSet {
    constructor(n) {
        this.father = new Array(n);
        for (var i = 0; i < n; i++) this.father[i] = i;
    }
    find(x) {
        return this.father[x] = (this.father[x] == x ? x : this.find(this.father[x]));
    }
    merge(a, b) {
        this.father[this.find(a)] = this.find(b); 
    } 
};
var removeStones = function(stones) {
    var u = new UnionSet(stones.length);
    var map_x = new Map(), map_y = new Map();
    for (var i = 0; i < stones.length; i++) {
        if (map_x.has(stones[i][0])) u.merge(i, map_x.get(stones[i][0]));
        if (map_y.has(stones[i][1])) u.merge(i, map_y.get(stones[i][1]));
        map_x.set(stones[i][0], i);
        map_y.set(stones[i][1], i);
    }
    var cnt = 0;
    for (var i = 0; i < stones.length; i++) {
        if (u.find(i) == i) cnt++;
    }
    return stones.length - cnt;
};