day55|并查集

107. 寻找存在的路径 (kamacoder.com)

#include<vector>
#include<iostream>

using namespace std;
int n = 0;
vector<int> father = vector<int>(101);
void init(){
    for(int i = 1; i < n + 1; i++){
        father[i] = i;
    }
}
int find(int i){  // 找根节点
    if(i == father[i]){
        return i;
    }
    return father[i] = find(father[i]); // 压缩作用，直接将i链接到根部
}
void join(int i, int j){
    i = find(i);
    j = find(j);
    if(i == j){
        return;
    }
    father[j] = i;
}
bool ifsame(int i, int j){
    i = find(i);
    j = find(j);
    return i == j;
}

int main(){
    int m = 0;
    cin >> n >> m;
    init();
    for(int i = 0; i < m; i++){
        int u = 0, v = 0;
        cin >> u >> v;
        join(u, v);
    }
    int s = 0, t = 0;
    cin >> s >> t;
    if(ifsame(s, t)){
        cout << 1 << endl;
    }else{
        cout << 0 << endl;
    }
    return 0;
}