Hdu2544 最短路【最短路】

http://acm.hdu.edu.cn/showproblem.php?pid=2544

不解释，最短路裸题

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#include <queue>
using namespace std;
template <class T> void checkmin(T &t,T x) {if(x < t) t = x;}
template <class T> void checkmax(T &t,T x) {if(x > t) t = x;}
template <class T> void _checkmin(T &t,T x) {if(t==-1) t = x; if(x < t) t = x;}
template <class T> void _checkmax(T &t,T x) {if(t==-1) t = x; if(x > t) t = x;}
typedef pair <int,int> PII;
typedef pair <double,double> PDD;
typedef long long ll;
#define foreach(it,v) for(__typeof((v).begin()) it = (v).begin(); it != (v).end ; it ++)
const int N = 111 , M = 20000;
#define inf (1<<29)
int n , m ;
int dist[N];
bool vis[N];
struct Edge {
    int v , w , next;
    Edge () {}
    Edge(int v,int w,int next) : v(v),w(w),next(next) {}
}edge[M];
int E , head[N];
void init() {
    E = 0; memset(head,-1,sizeof(head));
}
void addedge(int u,int v,int w) {
    edge[E] = Edge(v,w,head[u]);
    head[u] = E++;
    edge[E] = Edge(u,w,head[v]);
    head[v] = E++;
}
queue <int> q;
void spfa() {
    for(int i=1;i<=n;i++) dist[i] = inf , vis[i] = 0;
    while(!q.empty()) q.pop();
    q.push(1);
    dist[1] = 0;
    while(!q.empty()) {
        int u = q.front(); q.pop();
        vis[u] = 0;
        for(int i=head[u];i!=-1;i=edge[i].next) {
            int v = edge[i].v;
            if(dist[u] + edge[i].w < dist[v]) {
                dist[v] = dist[u] + edge[i].w;
                if(!vis[v]) {
                    vis[v] = 1;
                    q.push(v);
                }
            }
        }
    }
}
int main() {
    while(~scanf("%d%d",&n,&m) && n+m) {
        init();
        for(int i=0;i<m;i++) {
            int u , v , w;
            scanf("%d%d%d",&u,&v,&w);
            addedge(u , v , w);
        }
        spfa();
        printf("%d\n" , dist[n]);
    }
    return 0;
}