易爆物（X-Plosives ）基础并查集

复制代码

#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 100000 + 10;
int fa[maxn];

int Find(int x){
    if (x == fa[x])
        return x;
    else
        return fa[x] = Find(fa[x]);
}

int main(){
    int a, b;
    while (cin >> a){
        
        //init
        for (int i = 0; i < maxn; i++)
            fa[i] = i;
        int ans = 0;
        while (a != -1){
            cin >> b;
            a = Find(a);
            b = Find(b);
            if (a == b)
                ans++;
            else
                fa[b] = a;
            cin >> a;
        }
        cout << ans << endl;
    }
    //system("pause");
    return 0;
}