LA 3644 易爆物

https://vjudge.net/problem/UVALive-3644

简单的并查集题目。

#include<iostream>
using namespace std;

const int maxn = 100000 + 5;

int p[maxn];

int find(int x)
{
    return p[x] != x ? p[x] = (find(p[x])) : x;
}

int main()
{
    //freopen("D:\txt.txt", "r", stdin);
    int x, y;
    while (cin >> x && x != -1)
    {
        for (int i = 0; i < maxn; i++)
            p[i] = i;
        int cnt = 0;
        while (x != -1)
        {
            cin >> y;
            x = find(x);
            y = find(y);
            if (x == y)   cnt++;
            else p[x] = y;
            cin >> x;
        }
        cout << cnt << endl;
    }
}