hdu 1078 FatMouse and Cheese(记忆化搜索)

题目链接：acm.hdu.edu.cn/showproblem.php?pid=1078

FatMouse and Cheese

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)

Total Submission(s): 7985    Accepted Submission(s): 3336

Problem Description

FatMouse has stored some cheese in a city. The city can be considered as a square grid of dimension n: each grid location is labelled (p,q) where 0 <= p < n and 0 <= q < n. At each grid location Fatmouse has hid between 0 and 100 blocks of cheese in a hole. Now he's going to enjoy his favorite food.

FatMouse begins by standing at location (0,0). He eats up the cheese where he stands and then runs either horizontally or vertically to another location. The problem is that there is a super Cat named Top Killer sitting near his hole, so each time he can run at most k locations to get into the hole before being caught by Top Killer. What is worse -- after eating up the cheese at one location, FatMouse gets fatter. So in order to gain enough energy for his next run, he has to run to a location which have more blocks of cheese than those that were at the current hole.

Given n, k, and the number of blocks of cheese at each grid location, compute the maximum amount of cheese FatMouse can eat before being unable to move. 

 

Input

There are several test cases. Each test case consists of 

a line containing two integers between 1 and 100: n and k 
n lines, each with n numbers: the first line contains the number of blocks of cheese at locations (0,0) (0,1) ... (0,n-1); the next line contains the number of blocks of cheese at locations (1,0), (1,1), ... (1,n-1), and so on. 
The input ends with a pair of -1's. 

 

Output

For each test case output in a line the single integer giving the number of blocks of cheese collected. 

 

Sample Input

   
   
   
   

    
    
    
    3 1
1 2 5
10 11 6
12 12 7
-1 -1
   
   
   
   

 

Sample Output

   
   
   
   

    
    
    
    37
   
   
   
   

 

Source

Zhejiang University Training Contest 2001

 

题目大意： 老鼠每次只能走k步停下来，停下的这个位置只能比上一个停留的位置大，并获取其价值，每次只能水平或垂直走，问最大能得到的价值。

详见代码。

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

using namespace std;

int Map[110][110];
int dp[110][110];
int dir[4][2]= {1,0,-1,0,0,1,0,-1};
int n,k;

int dfs(int x,int y)
{
    int ans=0;
    if (!dp[x][y])
    {
        for (int i=0; i<4; i++)
        {
            for (int j=1; j<=k; j++)
            {
                int X=x+dir[i][0]*j;//乘以j表示走了几步
                int Y=y+dir[i][1]*j;
                if (X>=1&&X<=n&&Y>=1&&Y<=n)
                {
                    if (Map[X][Y]>Map[x][y])
                    {
                       ans=max(ans,dfs(X,Y));
                    }
                }
            }
        }
        dp[x][y]=ans+Map[x][y];
    }
    return dp[x][y];
}

int main()
{
    while (~scanf("%d%d",&n,&k))
    {
        memset(dp,0,sizeof(dp));
        if (n==-1&&k==-1)
            break;
        for(int i=1; i<=n; i++)
        {
            for (int j=1; j<=n; j++)
            {
                scanf("%d",&Map[i][j]);
            }
        }
        int Max=dfs(1,1);
        printf ("%d\n",Max);
    }
    return 0;
}