HDU-3047-Zjnu Stadium

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ACM模版

描述

题解

带权并查集，题真难读。

代码

#include <cstdio>#include <cmath>using namespace std;const int MAXN = 50005;int n, m;int pre[MAXN];int rank_[MAXN];void init(){    for (int i = 0; i <= n; ++i)    {        pre[i] = i;        rank_[i] = 0;    }}int find(int x){    if (x == pre[x])    {        return pre[x];    }    int t = pre[x];    pre[x] = find(pre[x]);    rank_[x] += rank_[t];    return pre[x];}bool join(int x, int y, int m){    int fx = find(x);    int fy = find(y);    if (fx == fy)    {        if (rank_[x] + m != rank_[y])        {            return false;        }        return true;    }    pre[fy] = fx;    rank_[fy] = rank_[x] + m - rank_[y];    return true;}int main(){    int a, b, x;    while (~scanf("%d%d", &n, &m))    {        init();        int cnt = 0;        for (int i = 0; i < m; ++i)        {            scanf("%d%d%d", &a, &b, &x);            if (!join(a, b, x))            {                ++cnt;            }        }        printf("%d\n", cnt);    }    return 0;}

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