传送门：POJ 2387 Til the Cows Come Home

千万看清点数和路径数的输入顺序。否则。你会像我一样WA和RE一个下午。

#include <iostream>
#include <vector>
#include <queue>
#include <string.h>
#define INF 0x3f3f3f3f
using namespace std;
const int maxn = 1024;
int n, t;
int dis[maxn], w[maxn][maxn];
int vis[maxn];

void spfa_bfs(int u)
{
    for(int i = 1; i <= n; ++i)
        dis[i] = INF, vis[i] = 0;
    dis[u] = 0;
    queue <int> q;
    q.push(u);
    vis[u] = 1;

    while(!q.empty())
    {
        int cur = q.front();
        q.pop();
        vis[cur] = 0;
        for(int i = 1; i <= n; ++i)
        {
            if(w[cur][i] && dis[i] > dis[cur]+w[cur][i])
            {
                dis[i] = dis[cur]+w[cur][i];
                if(!vis[i])
                {
                    q.push(i);
                    vis[i] = 1;
                }
            }
        }
    }
}

void read()
{
    cin >> t >> n;
    for(int i = 1; i <= n; ++i)
        for(int j = 1; j <= n; ++j)
            w[i][j] = (i == j) ? 0 : INF;
    for(int i = 0; i < t; ++i)
    {
        int u, v, l;
        cin >> u >> v >> l;
        if(w[u][v] > l)
            w[u][v] = w[v][u] = l;
    }
}

void solve()
{
    spfa_bfs(1);
    cout << dis[n] << '\n';
}

int main()
{
    read();
    solve();
	return 0;
}