POJ 2387 Til the Cows Come Home

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http://poj.org/problem?id=2387

使用bellman_ford解决最短路问题。

#include <stdio.h>#include <string.h>#include <iostream>#include <algorithm>using namespace std;int V,E,num,dis[1010];struct edge{    int from;    int to;    int v;}node[2010 << 1];void bellman_ford(int scr){    for(int i=1; i<=V; i++)        dis[i] = 1e9;    dis[scr] = 0;    bool flag;    for(int i=0; i<V-1; i++){        flag = false;        for(int j=1; j<=num; j++){            if(dis[node[j].to] > dis[node[j].from] + node[j].v){                dis[node[j].to] = dis[node[j].from] + node[j].v;                flag = true;            }        }        if(!flag)   break;    }}int main(){//    freopen("in.txt", "r", stdin);    num = 0;    scanf("%d%d",&E,&V);    int a,b,c;    for(int i=0; i<E; i++){        scanf("%d%d%d",&a,&b,&c);        num++;        node[num].from = a;        node[num].to = b;        node[num].v = c;        num++;        node[num].from = b;        node[num].to = a;        node[num].v = c;    }    bellman_ford(V);    printf("%d\n",dis[1]);    return 0;}

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