ACM Contest and Blackout - UVA 10600 - 次小生成树

ACM Contest and Blackout - UVA 10600 - 次小生成树

题意

思路

代码

//
//  main.cpp
//  L
//
//  Created by LucienShui on 2017/7/2.
//  Copyright © 2017年 LucienShui. All rights reserved.
//

#include <iostream>
#include <algorithm>
#include <set>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <stack>
#include <iomanip>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cctype>
#define memset(a,b) memset(a,b,sizeof(a))
#define il inline
#define ll long long
#define ull unsigned long long

using namespace std;

#define maxn 107

const int INF = 0x3f3f3f3f;
int T,n,m,ans,ans2,pre[maxn],fa[maxn];
struct node {
int a, b, c;
bool operator < (const node& tmp) const {
return c < tmp.c;
}
}a[maxn*maxn];
vector<node> used;
int find(int x, int pre[]) { return pre[x] == x ? x : pre[x] = find(pre[x], pre); }
void solve() {
sort(a, a+m);
int cnt = 1;
ans = 0;
used.clear();
for(int i=1;i<=n;i++) pre[i] = i;
for(int i=0;i<m;i++) {
int x = find(a[i].a, pre), y = find(a[i].b, pre);
if(x != y) {
pre[x] = y;
used.push_back(a[i]);
++cnt;
ans += a[i].c;
}
if(cnt == n) break;
}
ans2 = INF;
for(int i=0;i<used.size();i++) {
node v = used[i];
int cur = 0, cnt = 1;
for(int j=1;j<=n;j++) fa[j] = j;
for(int j=0;j<m;j++) {
if(v.a == a[j].a && v.b == a[j].b && v.c == a[j].c) continue;
int x = find(a[j].a, fa), y = find(a[j].b, fa);
if(x != y) {
fa[x] = y;
++cnt;
cur += a[j].c;
}
if(cnt == n) break;
}
if(cnt == n) ans2 = min(ans2, cur);
}
}

int main() {
#ifndef ONLINE_JUDGE
freopen("in.txt", "r", stdin);
#endif
scanf("%d",&T);
while(T--) {
scanf("%d%d",&n,&m);
for(int i=0;i<m;i++) scanf("%d%d%d",&a[i].a,&a[i].b,&a[i].c);
solve();
printf("%d %d\n",ans,ans2);
}
return 0;
}