HDU 1078 FatMouse and Cheese 简单记忆化搜索

Posted 2020-10-03 EricJeffrey

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

题目大意：在一个N*N的网格中每个网格都有一些奶酪，小明从(0,0)出发拿奶酪吃。但是小明只能往比当前网格中奶酪量多的网格走，并且小明一次最多可以一下子走k不。问小明能拿到多少奶酪吃？

解题思路：简单记忆化搜索一下就行。访问到一个网格， 如果该网格已经搜过，就直接返回记录的值。

代码：

 1 const int inf = 0x3f3f3f3f;
 2 const int maxn = 1e2 + 5; 
 3 int n, m;
 4 int dp[maxn][maxn];
 5 int maze[maxn][maxn];
 6 
 7 
 8 int dfs(int si, int sj){
 9     if(dp[si][sj]) return dp[si][sj];
10     int ans = maze[si][sj], tmans = 0;
11     for(int i = 1; i <= m; i++){
12         int u = si + i;
13         if(u < n && maze[u][sj] > maze[si][sj]){
14             tmans = max(tmans, dfs(u, sj));
15         }
16         u = si - i;
17         if(u >= 0 && maze[u][sj] > maze[si][sj]){
18             tmans = max(tmans, dfs(u, sj));
19         }
20         u = sj + i;
21         if(u < n && maze[si][u] > maze[si][sj]){
22             tmans = max(tmans, dfs(si, u));
23         }
24         u = sj - i;
25         if(u >= 0 && maze[si][u] > maze[si][sj]){
26             tmans = max(tmans, dfs(si, u));
27         }
28     }
29     return dp[si][sj] = ans + tmans;
30 }
31 int main(){
32     while(scanf("%d %d", &n, &m) && n != -1){
33         memset(dp, 0, sizeof(dp));
34         for(int i = 0; i < n; i++){
35             for(int j = 0; j < n; j++){
36                 scanf("%d", &maze[i][j]);
37             }
38         }
39         int ans = dfs(0, 0);
40         printf("%d\n", ans);
41     }
42 }

题目：

FatMouse and Cheese

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 11053    Accepted Submission(s): 4693

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