HDOJ 2544 BellmanFord实现

#include <cstdio>

struct road{
    int head;
    int tail;
    int value;
};

#define Infinity 233333333

int main(){
    int n, m;
    while (scanf("%d %d", &n, &m), n != 0){
        road roads[m];
        int dis[n];
        for (int i = 0; i < m; i++)
            scanf("%d %d %d", &roads[i].head, &roads[i].tail, &roads[i].value);
        dis[0] = 0;
        for (int i = 1; i < n; i++)
            dis[i] = Infinity;
        for (int i = 0; i < n - 1; i++)
            for (int j = 0; j < m; j++){
                int head, tail;
                if (dis[roads[j].tail - 1] > dis[roads[j].head - 1]){
                    head = roads[j].head - 1;
                    tail = roads[j].tail - 1;
                }
                else{
                    head = roads[j].tail - 1;
                    tail = roads[j].head - 1;
                }
                if (dis[tail] > dis[head] + roads[j].value)
                    dis[tail] = dis[head] + roads[j].value;
            }
        printf("%d
", dis[n - 1]);
    }
    return 0;
}