最短路 Dijkstra算法（CDOJ 最短路）

PS：

附上CDOJ最短路的另外一发代码：

http://www.acm.uestc.edu.cn/#/problem/show/30

#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <bitset>
#include <string>
#include <numeric>
#include <algorithm>
#include <functional>
#include <iterator>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <complex>
#include <ctime>
#define INF 0x3f3f3f3f
#define eps 1e-6

typedef long long LL;
const double pi = acos(-1.0);
const long long mod = 1e9 + 7;
using namespace std;

int a[105][105];
int dis[105];
bool vis[105];

int main()
{
    //freopen("int.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    int N,M;
    while(scanf("%d %d",&N,&M) != EOF)
    {
        if(N == 0 && M == 0)
            break;
        for(int i = 1;i <= N;i++)
            for(int j = 1;j <= N;j++)
                a[i][j] = INF;
        int A,B,C;
        for(int i = 1;i <= M;i++)
        {
            scanf("%d %d %d",&A,&B,&C);
            a[A][B] = a[B][A] = C;
        }
        memset(vis,0,sizeof(vis));
        for(int i = 1;i <= N;i++)
            dis[i] = INF;
        dis[1] = 0;
        for(int i = 1;i <= N;i++)
        {
            int minp = -1;
            int mind = INF;
            for(int j = 1;j <= N;j++)
            {
                if(!vis[j] && dis[j] < mind)
                {
                    mind = dis[j];
                    minp = j;
                }
            }
            if(minp == -1 || minp == N)
                break;
            vis[minp] = 1;
            for(int j = 1;j <= N;j++)
            {
                if(!vis[j])
                    dis[j] = min(mind + a[minp][j] , dis[j]);
            }
        }
        if(dis[N] >= INF)
            puts("Impossible");
        else
            printf("%d\n",dis[N]);
    }
    return 0;
}