LightOJ 1019 Brush (V) 最短路裸题

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题目：http://www.lightoj.com/volume_showproblem.php?problem=1019

题意：求从1到n的最短路。。。

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <queue>using namespace std;const int N = 110, INF = 0x3f3f3f3f;struct edge{    int to, cost, next;}g[N*N*2];int cnt, head[N], dis[N];bool vis[N];int n, m, cas;void add_edge(int v, int u, int cost){    g[cnt].to = u, g[cnt].cost = cost, g[cnt].next = head[v], head[v] = cnt++;    g[cnt].to = v, g[cnt].cost = cost, g[cnt].next = head[u], head[u] = cnt++;}int spfa(int s, int t){    memset(dis, 0x3f, sizeof dis);    memset(vis, 0, sizeof vis);    queue<int> que;    que.push(s), dis[s] = 0, vis[s] = true;    while(! que.empty())    {        int v = que.front(); que.pop();        vis[v] = false;        for(int i = head[v]; i != -1; i = g[i].next)        {            int u = g[i].to;            if(dis[u] > dis[v] + g[i].cost)            {                dis[u] = dis[v] + g[i].cost;                if(! vis[u]) que.push(u), vis[u] = true;            }        }    }    return dis[t];}int main(){    int t, a, b, c;    scanf("%d", &t);    while(t--)    {        cnt = 0;        memset(head, -1, sizeof head);        scanf("%d%d", &n, &m);        for(int i = 0; i < m; i++) scanf("%d%d%d", &a, &b, &c), add_edge(a, b, c);        int res = spfa(1, n);        if(res == INF) printf("Case %d: Impossible\n", ++cas);        else printf("Case %d: %d\n", ++cas, res);    }    return 0;}

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