# 【luogu P3959 宝藏】 题解

code：

#include <queue>
#include <ctime>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
const int maxn = 10000;
const int inf = 0x7fffffff;
int ma[13][13], deep[maxn], n, m, ans;
struct edge{
int u, v;
};
bool operator < (struct edge a, struct edge b)
{
return deep[a.u] * ma[a.u][a.v] > deep[b.u] * ma[b.u][b.v];
}
int sear(int s)//s 起点
{
int cnt = 0, cost = 0;
bool vis[maxn];
edge e[maxn], now, now2;
priority_queue<edge> q;
memset(deep, 0, sizeof(deep));
memset(vis, 0, sizeof(vis));
deep[s] = 1, vis[s] = 1;
for(int i = 1; i <= n; i++)
if(ma[s][i] < inf)
{
now.u = s, now.v = i;
//cout<<now.u<<" "<<now.v<<endl;
q.push(now);
}
for(int i = 1; i <= n-1; i++)
{
now = q.top(); q.pop();
while(!q.empty() && ((vis[now.v] || rand()%(n) < 1)))
{
if(!vis[now.v]) e[++cnt] = now;
now = q.top(); q.pop();
}
vis[now.v] = 1, deep[now.v] = deep[now.u] + 1;
//cout<<cnt;
for(int i = 1; i <= cnt; i++) q.push(e[i]);
for(int i = 1; i <= n; i++)
{
if(ma[now.v][i] != inf && !vis[i])
{
now2.u = now.v; now2.v = i;

q.push(now2);
}
}
cost += ma[now.u][now.v] * deep[now.u];
}
return cost;
}
int main()
{
scanf("%d%d",&n,&m);
for(int i = 1; i <= n; i++)
for(int j = 1; j <= n; j++) ma[i][j] = inf;
for(int i = 1; i <= m; i++)
{
int u, v, w;
scanf("%d%d%d",&u,&v,&w);
ma[u][v] = min(w, ma[u][v]);
ma[v][u] = min(w, ma[v][u]);
}
srand(192608);
ans = inf;

for(int i = 1; i <= 500; i++)
{
for(int j = 1; j <= n; j++)
ans = min(ans, sear(j));
}
printf("%d",ans);
return 0;
}

posted @ 2018-10-29 20:18  Misaka_Azusa  阅读(90)  评论(0编辑  收藏
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