Little Busters! — 并查集

题目链接：http://acm.buaa.edu.cn/problem/418/

代码：

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;

const int maxn = 550;
const int maxe = 5050;
const int INF = 0x3f3f3f3f;

int pa[maxn];
int find(int x)
{
    return x == pa[x] ? x : pa[x] = find(pa[x]);
}
struct Edge
{
    int u,v,w;
    bool operator < (const Edge& rhs) const
    {
        return w > rhs.w;
    }
} e[maxe];

int s,t;
int n,m;
int Max,Min;

void solve()
{
    for(int i=1; i<=m; i++)
    {
        for(int j=1; j<=n; j++) pa[j] = j;

        int j;
        for(j=i; j<=m; j++)
        {
            int ufa = find(e[j].u);
            int vfa = find(e[j].v);
            if(ufa != vfa)
            {
                pa[vfa] = ufa;
            }
            if(find(s) == find(t)) break;
        }
        if(j > m) return;
        if(Max*e[j].w > Min*e[i].w)
        {
            Max = e[i].w;
            Min = e[j].w;
        }
     }
}

int main()
{
    //freopen("/home/raidy/桌面/shaynelq/beihang8_contest/input.txt","r",stdin);
    int T;
    cin>>T;

    while(T --)
    {
        scanf("%d %d",&n,&m);
        for(int i=1; i<=m; i++)
        {
            scanf("%d %d %d",&e[i].u,&e[i].v,&e[i].w);
        }
        sort(e+1,e+m+1);
        scanf("%d %d",&s,&t);
        Max = 30000,Min = 0;
        solve();
        if(Max == 30000 && Min == 0)
        {
            printf("R U Kiddin'?
");
            continue;
        }
        int g = __gcd(Max,Min);
        Max /= g;
        Min /= g;
        if(Min == 1) printf("%d
",Max);
        else         printf("%d/%d
",Max,Min);
    }
}