hdu-2544-最短路（Bellman-Ford算法模板）

题目链接

题意很清晰，入门级题目，适合各种模板，可用dijkstra, floyd, Bellman-ford, spfa

Dijkstra链接

Floyd链接

Bellman-Ford链接

SPFA链接

/*
    Name:HDU-2544-最短路
    Copyright:
    Author:
    Date: 2018/4/17 10:34:47
    Description:
        man-ford 
*/
#include <cstring>
#include <cstdio>
#include <iostream>
using namespace std; 
const int MAXN = 105;
const int INF = 0x3f3f3f3f;
int dis[MAXN], g[MAXN][MAXN], N, M;
bool v[MAXN];
void bellman_ford()
{
    int i,j;
    memset(dis, 0x3f, sizeof(dis));
    dis[1]=0;
    bool update=true;
    while(update){
        update=false;
        for(i=1;i<=N;++i){
            for(j=1;j<=N;++j){
                if(g[i][j]!=INF&&dis[j]>dis[i]+g[i][j]){
                    dis[j]=dis[i]+g[i][j];
                    update=true;
                }
            }
        }
        if (!update) return;//优化 
    }
}
int main()
{
//    freopen("in.txt", "r", stdin);
    while (~scanf("%d %d", &N, &M) && (N+M)) {
        memset(g, 0x3f, sizeof(g));
        for (int i=0; i<M; i++) {
            int a, b, c;
            scanf("%d %d %d", &a, &b, &c);
            if (g[a][b] > c) {
                g[a][b] = g[b][a] = c;
            }
        }
        bellman_ford();
        printf("%d
", dis[N]);
    }
    return 0;
}