poj3767

最短路

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

#define maxn 605
#define maxm 10005
#define inf 0x3f3f3f3f

struct Edge
{
    int v, next, w;
}edge[maxm * 2];

int n, m;
int id[maxn];
int ecount, head[maxn];
int lowcost[maxn];
bool vis[maxn];

void addedge(int a, int b, int w)
{
    edge[ecount].v = b;
    edge[ecount].next = head[a];
    edge[ecount].w = w;
    head[a] = ecount++;
}

void input()
{
    scanf("%d", &m);
    ecount = 0;
    memset(head, -1, sizeof(head));
    for (int i = 0; i < m; i++)
    {
        int a, b, w;
        scanf("%d%d%d", &a, &b, &w);
        a--;
        b--;
        addedge(a, b, w);
        addedge(b, a, w);
    }
    for (int i = 0; i < n; i++)
        scanf("%d", &id[i]);
}

void dijkstra()
{
    memset(vis, 0, sizeof(vis));
    for (int i = 0; i < n; i++)
        lowcost[i] = inf;
    vis[0] = true;
    lowcost[0] = 0;
    int u = 0;
    while (~u)
    {
        for (int i = head[u]; ~i; i = edge[i].next)
        {
            int v = edge[i].v;
            if (vis[v])
                continue;
            if (id[u] != id[0] && id[v] == id[0])
                continue;
            lowcost[v] = min(lowcost[v], lowcost[u] + edge[i].w);
        }
        u = -1;
        int low = inf;
        for (int i = 0; i < n; i++)
            if (!vis[i] && lowcost[i] < low)
            {
                low = lowcost[i];
                u = i;
            }
        vis[u] = true;
    }
}

int main()
{
    //freopen("t.txt", "r", stdin);
    while (scanf("%d", &n), n)
    {
        input();
        dijkstra();
        if (lowcost[1] == inf)
            printf("-1\n");
        else
            printf("%d\n", lowcost[1]);
    }
    return 0;
}