A - Structure FIG Exercise - the shortest path (Dijkstra)

Description

Given a weighted undirected graph, the shortest path node 1 to node n.

Input

Comprising a plurality of sets of input data format.
The first line includes two integer number representative of the number of nodes and edges nm. (n <= 100)
remaining between the m lines each have three ABC positive integer, and a representative node of a node b side, a weight of c.

Output

Each group of outputs per line, only the output from the shortest path weight 1 to n. (To ensure the presence of the shortest path)

Sample

Input

3 2
1 2 1
1 3 1
1 0
Output

1
0

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<malloc.h>
#include<queue>
#define INF 0x3f3f3f3f
using namespace std;
int n,m;
int dis[110],vis[110],Map[110][110];
void dijstra()
{

    for(int i=1;i<=n;i++)
    {
        dis[i] = Map[1][i];
    }
    vis[1] = 1;
    for(int i=2;i<=n;i++)
    {
        int Min = INF;
        int flag;
        for(int j=1;j<=n;j++)
        {
            if(!vis[j]&&dis[j]<Min)
            {
                Min = dis[j];
                flag = j;
            }
        }
        vis[flag] = 1;
        for(int j=1;j<=n;j++)
        {
            if(dis[j]>Map[flag][j]+dis[flag])
                dis[j] = Map[flag][j]+dis[flag];
        }
    }
    printf("%d\n",dis[n]);
}
int main()
{
    int u,v,w;
    while(~scanf("%d %d",&n,&m))
    {
        memset(Map,INF,sizeof(Map));
        memset(dis,INF,sizeof(dis));
        memset(vis,0,sizeof(vis));
        if(m==0)
            printf("0\n");
        else
        {
            for(int i=0; i<m; i++)
            {
                scanf("%d %d %d",&u,&v,&w);
                if(Map[u][v]>w)
                {
                    Map[u][v]=Map[v][u]=w;
                }
            }
            dijstra();
        }
    }
    return 0;
}