POJ 1125-Stockbroker Grapevine-最短路

裸最短路

/*--------------------------------------------------------------------------------------*/
//        Helica's header 
//        Second Edition
//        2015.11.7
//
#include <algorithm>
#include <iostream>
#include <cstring>
#include <ctype.h>
#include <cstdlib>
#include <cstdio>
#include <vector>
#include <string>
#include <queue>
#include <stack>
#include <cmath>
#include <set>
#include <map>

//debug function for a N*M array 
#define debug_map(N,M,G) printf("\n");for(int i=0;i<(N);i++)\
{for(int j=0;j<(M);j++){\
printf("%d",G[i][j]);}printf("\n");}                
//debug function for int,float,double,etc.
#define debug_var(X) cout<<#X"="<<X<<endl;
/*--------------------------------------------------------------------------------------*/
using namespace std;

const int INF = 0x3f3f3f3f;
const int MAXN = 300;
int N,M,T;
struct qnode
{
    int v,c;
    qnode(int _v=0,int _c=0):v(_v),c(_c){}
    bool operator < (const qnode &r) const
    {return c > r.c;}
};

struct Edge{
    int v,cost;
    Edge(int _v=0,int _cost=0):v(_v),cost(_cost){}
};

vector <Edge> E[MAXN];
bool vis[MAXN];
int dist[MAXN];

int Dijkstra(int n,int start)
{
    memset(vis,false,sizeof vis);
    for(int i=1;i<=n;i++) dist[i] = INF;
    priority_queue<qnode> que;
    while(!que.empty()) que.pop();
    dist[start] = 0;
    que.push(qnode(start,0));
    qnode tmp;
    while(!que.empty())
    {
        tmp = que.top();
        que.pop();
        int u = tmp.v;
        if(vis[u]) continue;
        vis[u] = true;
        for(int i=0;i<(int)E[u].size();i++)
        {
            int v = E[u][i].v;
            int cost = E[u][i].cost;
            if(!vis[v]&&dist[v]>dist[u]+cost)
            {
                dist[v] = dist[u]+cost;
                que.push(qnode(v,dist[v]));
            }
        }
    }
    int ans = 0;
    for(int i=1;i<=n;i++) ans = max(ans,dist[i]);
    //printf("start:%d max:%d\n",start,ans);
    return ans;
}

void addedge(int u,int v,int w)
{
    E[u].push_back(Edge(v,w));
}

int main()
{
    while(scanf("%d",&N) && N)
    {
        for(int i=0;i<MAXN;i++) E[i].clear();
        for(int i=1,m,id,t;i<=N;i++)
        {
            scanf("%d",&m);
            for(int j=0;j<m;j++)
            {
                scanf("%d%d",&id,&t);
                addedge(i,id,t);
            }
        }

        int res = INF,resid = 0;
        for(int i=1,tmp;i<=N;i++)
        {
            tmp = Dijkstra(N,i);
            if(res > tmp)
            {
                res = tmp;
                resid = i;
            }
        }
        printf("%d %d\n",resid,res);
    }    
}