杭电5137--How Many Maos Does the Guanxi Worth（Spfa+暴力枚举）

题目：http://acm.hdu.edu.cn/showproblem.php?pid=5137

题意：话说题意很坑啊、第一次做这个题暴力枚举也想起来了, 但。。。。 题目说的是在路径中去任意除一个点， 看1~n是否还联通，求权值和最大的最短路的权值和，题目中给的点数最大是30，暴力枚举就出来了。 注意一点： Sp 和 Dij 中是对Map数组处理。

Spfa: 
#include <queue> 
#include <cstdio>
#include <cstring>
#include <iostream>
#define max(a, b) a>b?a:b
using namespace std;
const int INF = 0x3f3f3f3f;
int map[33][33], Map[33][33], dis[33], vis[33]; 
int n, m;
int Spfa(int a)
{
    memset(vis, 0, sizeof(vis));
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= n; j++)
        {
            if(i == a || j == a)
                Map[i][j] = INF;
            else 
                Map[i][j] = map[i][j]; 
        }
    for(int i = 1; i <= n; i++)
        dis[i]=INF; 
    dis[1] = 0; vis[1] = 1;
    queue<int> Q;
    Q.push(1);
    while(!Q.empty()) 
    {
        int temp = Q.front();
        Q.pop();  vis[temp] = 0;
        for(int j = 1; j <= n; j++)
            if(dis[j] > dis[temp] + Map[temp][j])
            {
                dis[j] = dis[temp] + Map[temp][j]; 
                if(!vis[j])
                {
                    vis[j] = 1;
                    Q.push(j);    
                }    
            } 
    }
    return dis[n];
} 
int main()
{
    while(scanf("%d %d", &n, &m), n+m)
    {
        for(int i = 1; i <= n; i++)
            for(int j = 1; j <= n; j++)
                map[i][j]=(i==j?0:INF);
        int u, v, w;
        for(int i = 1; i <= m; i++)
        {
            scanf("%d %d %d", &u, &v, &w);
            if(map[u][v] > w)
                map[u][v]=map[v][u]=w;
        }
        int ans = 0;
        for(int i = 2; i < n; i++)     //暴力枚举， 很精髓。 
            ans = max(ans, Spfa(i));
        if(ans == INF)
            printf("Inf
");
        else
            printf("%d
", ans); 
    }
    return 0;
} 

Dijkstra：练练模板。 
#include <cstdio>
#include <cstring>
#include <iostream>
#define max(a, b) a>b?a:b 
const int INF = 0x3f3f3f3f; 
using namespace std; 
int map[33][33], Map[33][33], dis[33], vis[33];
int n, m;
int Dijkstra(int a)
{
    memset(vis, 0, sizeof(vis));
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= n; j++)
        {
            if(i == a || j == a)
                Map[i][j] = INF;
            else
                 Map[i][j] = map[i][j]; 
        }    
    for(int i = 1; i <= n; i++)
        dis[i] = map[1][i];
    vis[1] = 1;
    for(int i = 1; i < n; i++)
    {
        int temp, min = INF;
        for(int j = 1; j <= n; j++)
        {
            if(!vis[j] && dis[j] < min)
            {
                temp = j;
                min = dis[j];
            }
        }
        vis[temp] = 1; 
        for(int j = 1; j <= n; j++)
            if(!vis[j] && dis[j] > dis[temp] + Map[temp][j])
                dis[j] = dis[temp] + Map[temp][j];
    }
    return dis[n];
} 
int main()
{
    while(scanf("%d %d", &n, &m), m+n)
    {
        for(int i = 1; i <= n; i++)
            for(int j = 1; j <= n; j++)
                map[i][j]=(i==j?0:INF);
        int u, v, w;
        for(int i = 1; i <= m; i++)
        {
            scanf("%d %d %d", &u, &v, &w);
            if(map[u][v] > w)
                map[u][v] = map[v][u] = w;
        }
        int maxx = 0;
        for(int i = 2; i < n; i++)
            maxx = max(maxx, Dijkstra(i));
        if(maxx == INF)
            printf("Inf
");
        else
            printf("%d
", maxx);
    }
    return 0;    
}