bzoj千题计划201：bzoj1820: [JSOI2010]Express Service 快递服务

#include<cstdio>
#include<cstring>
#include<iostream>

using namespace std;

#define M 201

int dis[M][M];
int dp[2][M][M];

void read(int &x)
{
    x=0; char c=getchar();
    while(!isdigit(c)) c=getchar();
    while(isdigit(c)) { x=x*10+c-‘0‘; c=getchar(); }
}

int main()
{
    int m;
    read(m);
    for(int i=1;i<=m;++i)
        for(int j=1;j<=m;++j)
            read(dis[i][j]);
    int x,last;
    read(last);
    memset(dp[0],63,sizeof(dp[0]));
    int inf=dp[0][0][0];
    dp[0][2][3]=dis[1][last];
    dp[0][1][3]=dis[2][last];
    dp[0][1][2]=dis[3][last];
    int u=1,v=0;
    while(scanf("%d",&x)!=EOF)
    {
        swap(u,v);
        memset(dp[v],63,sizeof(dp[v]));
        for(int i=1;i<=m;++i)
            for(int j=i;j<=m;++j)
                if(dp[u][i][j]!=inf)
                {
                    dp[v][i][j]=min(dp[v][i][j],dp[u][i][j]+dis[last][x]);
                    dp[v][min(last,j)][max(last,j)]=min(dp[v][min(last,j)][max(last,j)],dp[u][i][j]+dis[i][x]);
                    dp[v][min(last,i)][max(last,i)]=min(dp[v][min(last,i)][max(last,i)],dp[u][i][j]+dis[j][x]);
                }
        last=x;
    }
    int ans=inf;
    for(int i=1;i<=m;++i)
        for(int j=i;j<=m;++j)
            ans=min(ans,dp[v][i][j]);
    cout<<ans;
}