UESTC 881 神秘绑架案 --二维DP

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#define Mod 1000000007
using namespace std;
#define N 2100

double dp[17][9][9][9][9],sum[9][9][9][9],mp[9][9];

double SUM2(int i,int j,int a,int b)
{
if(sum[i][j][a][b] >= 0)
return sum[i][j][a][b];
double res = 0;
int k,h;
for(k=i;k<=a;k++)
for(h=j;h<=b;h++)
res += mp[k][h];
sum[i][j][a][b] = res*res;
return sum[i][j][a][b];
}

double solve(int k,int i,int j,int a,int b)
{
if(k == 1)
return SUM2(i,j,a,b);
if(dp[k][i][j][a][b] >= 0)
return dp[k][i][j][a][b];
double Min1 = Mod;
double Min2 = Mod;
for(int s=i;s<a;s++)
Min1 = min(Min1,min(solve(k-1,i,j,s,b)+SUM2(s+1,j,a,b),solve(k-1,s+1,j,a,b)+SUM2(i,j,s,b)));
for(int h=j;h<b;h++)
Min2 = min(Min2,min(solve(k-1,i,j,a,h)+SUM2(i,h+1,a,b),solve(k-1,i,h+1,a,b)+SUM2(i,j,a,h)));
dp[k][i][j][a][b] = min(Min1,Min2);
return dp[k][i][j][a][b];
}

int main()
{
double SUM,AX;
int i,j,n;
SUM = 0;
scanf("%d",&n);
for(i=1;i<=8;i++)
{
for(j=1;j<=8;j++)
{
scanf("%lf",&mp[i][j]);
SUM += mp[i][j];
}
}
AX = SUM/(double)n;
AX *= AX;
memset(sum,-1,sizeof(sum));
memset(dp,-1,sizeof(dp));
printf("%.3lf\n",sqrt(solve(n,1,1,8,8)/(double)n-AX));
return 0;
}