POJ 1191 Checkerboard Segmentation (compression dp+ memory Search)

One, test instructions:

Chinese questions

Second, analysis:

The main use of compressed DP and memory search ideas

Three, code:

#include <iostream> #include <stdio.h> #include <string.h> #include <stdlib.h> #include < math.h>using namespace Std;const int big=20000000;int mat[10][10];int n;int sum[10][10];int dp[20][10][10][10][10];    The Void unit () {//sum with SUM[I][J] represents the IJ to the upper-left corner and int total;            for (int i=1, i<=8; i++) for (int j=1; j<=8; J + +) {Total=mat[i][j];            int x_1,y_1;            X_1=i-1;            Y_1=j-1;            if (x_1>0) total+=sum[x_1][j];            if (y_1>0) total+=sum[i][y_1];            if (x_1>0&&y_1>0) total-=sum[x_1][y_1];        Sum[i][j]=total;    }}int account (int x_1,int y_1,int x_2,int y_2) {//Request (X_1,y_1) to (x_2,y_2) interval and int total=sum[x_2][y_2];    int x_3,y_3;    X_3=x_1-1;    Y_3=y_1-1;    if (x_3>0) total-=sum[x_3][y_2];    if (y_3>0) total-=sum[x_2][y_3];    if (x_3>0&&y_3>0) total+=sum[x_3][y_3]; return total*total;} INT Solve (int k,int x_1,int y_1,int x_2,int y_2) {//Memory DP if (DP[K][X_1][Y_1][X_2][Y_2]!=-1) return dp[k][x_1][y_1] [X_2]    [Y_2];    if (k==1) return Dp[k][x_1][y_1][x_2][y_2]=account (x_1,y_1,x_2,y_2);        if (k>1) {int min=big;            for (int i=y_1;i<y_2;i++) {//crosswise cut int first=account (x_1,y_1,x_2,i);            int Second=account (x_1,i+1,x_2,y_2);            First+=solve (k-1,x_1,i+1,x_2,y_2);            Second+=solve (K-1,x_1,y_1,x_2,i);            if (First>second) First=second;        if (Min>first) Min=first;            } for (int j=x_1;j<x_2;j++) {//lengthwise cut int first=account (x_1,y_1,j,y_2);            int Second=account (j+1,y_1,x_2,y_2);            First+=solve (k-1,j+1,y_1,x_2,y_2);            Second+=solve (k-1,x_1,y_1,j,y_2);            if (First>second) First=second;        if (Min>first) Min=first; } return dp[k][x_1][y_1][x_2][Y_2]=min; } return dp[k][x_1][y_1][x_2][y_2]=big;}        int main () {while (scanf ("%d", &n)!=eof) {double total=0.0;                 for (int. I=1; i<=8; i++) for (int j=1; j<=8; J + +) {scanf ("%d", &mat[i][j]);            TOTAL+=MAT[I][J];        } unit ();         Memset (Dp,-1,sizeof (DP));        Total= (total/n) * (total/n);        Double Key=solve (n,1,1,8,8);       key=key/n;       KEY=SQRT (key-total);    printf ("%0.3f\n", key); } return 0;}

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POJ 1191 Checkerboard Segmentation (compression dp+ memory Search)