【codevs2011】【LNOI2013】最小距离之和

floyed水题

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;

#define INF 30000000
#define N 210

struct Node
{
    int f,t,v;
    int ans;
}e[N];

int g[N][N];

int n,m;

int main()
{
    scanf("%d",&n);    
    for (int i=1;i<=n;i++)
        for (int j=1;j<=n;j++)
            scanf("%d",&g[i][j]);
    scanf("%d",&m);    
    for (int i=1;i<=m;i++)
    {
        scanf("%d%d",&e[i].f,&e[i].t);
        e[i].v=g[e[i].f][e[i].t];
        g[e[i].f][e[i].t]=INF;
    }
    for (int k=1;k<=n;k++)
        for (int i=1;i<=n;i++)
            for (int j=1;j<=n;j++)
                g[i][j]=min(g[i][j],g[i][k]+g[k][j]);
        for (int i=1;i<=n;i++)
        for (int j=1;j<=n;j++)
            e[m].ans+=g[i][j];
    for (int k=m;k>=1;k--)
    {
        for (int i=1;i<=n;i++)
            for (int j=1;j<=n;j++)
                g[i][j]=min(g[i][j],g[i][e[k].f]+g[e[k].t][j]+e[k].v);   
        for (int i=1;i<=n;i++)
            for (int j=1;j<=n;j++)
                e[k-1].ans+=g[i][j];
    }
    for (int i=1;i<=m;i++)
        if (e[i].ans>=INF)
            printf("INF
");
        else
            printf("%d
",e[i].ans);
    return 0;
}