zoj2750

#include<iostream>
#include<cstring>
#include<cstdio>
#include<string>
#include<algorithm>
using namespace std;
const int inf = 1000000000;
const int maxn = 1010;
int edge[maxn][maxn];
int s[maxn],dist[maxn],i,j,n;
struct node
{
    int t ; char front[5],back[5];
}dict[maxn];
void dijkstra()
{
    for(i=0;i<n;i++)
    {
        dist[i] = edge[0][i];
        s[i] = 1;
    }
    s[0] = -1;
    for(i=1;i<n;i++)
    {
        int min = inf,v=0;
        for(j=0;j<n;j++)
        {
            if(s[j]!=-1 && dist[j]<min)
            {
                min = dist[j];
                v = j;
            }
        }
        s[v] = -1;
        for(j=0;j<n;j++)
        {
            if(s[j]!=-1 && edge[v][j]<inf && edge[v][j]+dist[v]<dist[j])
            {
                dist[j] = edge[v][j] + dist[v];
            }
        }
    }
    if(dist[n-1] == inf)
        printf("-1
");
    else
    {
        printf("%d
",dist[n-1]);
    }
}
int main()
{
//    int n;
    while(scanf("%d",&n)!=EOF && n)
    {
        int k;char d[100];
        for(k=0;k<n;k++)
        {
            scanf("%d %s",&dict[k].t,d);
            int len = strlen(d);
            for(i=0,j=len-1;i<4;i++,j--)
            {
                dict[k].front[i] = d[i];
                dict[k].back[3-i] = d[j];
                dict[k].front[4]  = dict[k].back[4] = '';
            }

        }
        for(i=0;i<n;i++)
        {
            for(j=0;j<n;j++)
            {
                edge[i][j] = inf;
                if(i==j)
                    edge[i][j] = 0;
                //    continue;
                else if(strcmp(dict[i].back,dict[j].front) ==0)
                {
                    edge[i][j] = dict[i].t;
                }
            }
        }
        dijkstra();

    }
    return 0;
}