题意 :
       从起点0开始,到达最近的那个是海边的城镇的距离..

思路:
      水的最短路,随你怎么写,dij,floyd,spfa..都行,只要你喜欢..我写的spfa好久不写了,复习下. 



#include<stdio.h>
#include<queue>

#define N_node 10 + 5
#define N_edge 200 + 10
#define inf 1000000000

using namespace std;

typedef struct
{
   int to ,next ,cost;
}STAR;

STAR E[N_edge];
int list[N_node] ,tot;
int s_x[N_node];

void add(int a ,int b ,int c)
{
   E[++tot].to = b;
   E[tot].cost = c;
   E[tot].next = list[a];
   list[a] = tot;
}

void spfa(int s ,int n)
{
   for(int i = 0 ;i <= n ;i ++)
   s_x[i] = inf;
   s_x[s] = 0;
   int mark[N_node] = {0};
   mark[s] = 1;
   queue<int>q;
   q.push(s);
   while(!q.empty())
   {
      int xin ,tou;
      tou = q.front();
      q.pop();
      mark[tou] = 0;
      for(int k = list[tou] ;k ;k = E[k].next)
      {
         xin = E[k].to;
         if(s_x[xin] > s_x[tou] + E[k].cost)
         {
            s_x[xin] = s_x[tou] + E[k].cost;
            if(!mark[xin])
            {
               mark[xin] = 1;
               q.push(xin);
            }
         }
      }
   }
   return ;
}

int main ()
{
   int mk_hai[N_node];
   int i ,j ,n ,m ,p ,b ,c;
   while(~scanf("%d" ,&n))
   {
      memset(mk_hai ,0 ,sizeof(mk_hai));
      memset(list ,0 ,sizeof(list));
      tot = 1;
      for(i = 1 ;i <= n ;i ++)
      {
         scanf("%d %d" ,&m ,&p);
         if(p)mk_hai[i] = 1;
         for(j = 1 ;j <= m ;j ++)
         {
            scanf("%d %d" ,&b ,&c);
            add(i ,b + 1 ,c);
            add(b + 1 ,i ,c);
         }
      }
      spfa(1 ,n);
      int ans = inf;
      for(i = 1 ;i <= n ;i ++)
      if(mk_hai[i] && ans > s_x[i])
      ans = s_x[i];
      printf("%d\n" ,ans);
   }
   return 0;
}