hdu-2544-最短路(SPFA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:
    SPFA
*/
#include <cstring>
#include <cstdio>
#include <iostream>
#include <vector>
#include <queue>
#include <utility>
using namespace std; 
const int MAXN = 1010;
int  n, m;
vector <pair<int, int>> g[MAXN];
int dist[MAXN];
bool inQue[MAXN];
queue<int> que;
void spfa() {
    memset(inQue, 0, sizeof(inQue));
    memset(dist, 0x3f, sizeof(dist));
    dist[1] = 0;
    while (!que.empty()) que.pop();
    que.push(1);
    inQue[1] = true;
    while (!que.empty()) {
        int u = que.front();
        que.pop();
        inQue[u] = false;
        for (int i=0; i<g[u].size(); i++) {
            if(dist[u]+g[u][i].second < dist[g[u][i].first]) {
                dist[g[u][i].first] = dist[u] + g[u][i].second;
                if (!inQue[g[u][i].first]) {
                    inQue[g[u][i].first] = true;
                    que.push(g[u][i].first);
                }
            }
        }
    }
}
int main()
{
//    freopen("in.txt", "r", stdin);
    while (~scanf("%d %d", &n, &m) && (n+m)) {
        for (int i=0; i<=100; i++) {
            while (!g[i].empty()) {//  while
                g[i].pop_back();
            }
        }
        for (int i=1; i<=m; i++) {
            int a, b, c;
            scanf("%d %d %d", &a, &b, &c);
            g[a].push_back(make_pair(b, c));
            g[b].push_back(make_pair(a, c));
        }
        spfa();
        printf("%d
", dist[n]);
    }
    return 0;
}