杭电1078（记忆搜索）

 1 #include<stdio.h>
 2 #include<string.h>
 3 //#include<stdlib.h>
 4 /*#include<iostream>
 5 #include<algorithm>
 6 using namespace std;*/
 7 
 8 int getmax(int x, int y){
 9     return x > y ? x : y;
10 }
11 
12 typedef struct{
13     int x;
14     int y;
15 }List;
16 List list[10001];
17 
18 int dir[4][2]={0, -1, -1, 0, 0, 1, 1, 0};
19 
20 
21 int main(){
22     int n, k, block[101][101], i, j, ii, jj, dp[101][101], max, lastmax, startx, starty, start, num;
23     while(scanf("%d %d", &n, &k) && (n != -1 || k != -1)){
24         max = -1;
25         for(i = 0; i < n; i ++){
26             for(j = 0; j < n; j ++){
27                 scanf("%d", &block[i][j]);
28                 max = getmax(max, block[i][j]);
29             }
30         }
31         memset(dp, -1, sizeof(dp));
32         dp[0][0] = block[0][0];
33         start = dp[0][0];
34         startx = 0;
35         starty = 0;
36         num = 0;
37         lastmax = dp[0][0];
38         do{
39             for(i = 0; i < 4; i ++){
40                 if(block[startx][starty] == max){
41                     break;
42                 }
43                 for(j = 1; j <= k; j ++){
44                     ii = startx + dir[i][0] * j;
45                     jj = starty + dir[i][1] * j;
46                     if(ii < 0 || jj < 0 || ii >= n || jj >= n || block[ii][jj] <= block[startx][starty]){
47                         continue;
48                     }
49                     dp[ii][jj] = getmax(dp[ii][jj], start + block[ii][jj]);
50                     lastmax = getmax(dp[ii][jj], lastmax);
51                     list[num].x = ii;
52                     list[num ++].y = jj;
53                 }
54             }
55             if(num == 0){
56                 num --;
57                 continue;
58             }
59             startx = list[-- num].x;
60             starty = list[num].y;
61             start = dp[startx][starty];
62         }while(num != -1);
63         printf("%d\n", lastmax);
64     }
65     return 0;
66 }

 1 #include<stdio.h>
 2 #include<string.h>
 3 
 4 int map[105][105];
 5 int value[105][105];
 6 int dir[4][2]={0,1,0,-1,1,0,-1,0};
 7 int n,k;
 8 
 9 int dfs(int sx,int sy)
10 {
11    int i,j,x,y,max=0,temp;
12    if(value[sx][sy]!=-1)       //该点已经计算过，直接返回值
13       return value[sx][sy];
14    for(i=0;i<4;i++)            //2个循环控制该点所能走的地方
15      for(j=1;j<=k;j++)
16      {
17         x=sx+dir[i][0]*j;
18         y=sy+dir[i][1]*j;
19         if(x<0||x>=n||y<0||y>=n||map[x][y]<=map[sx][sy])    //剪枝
20           continue;
21         temp=dfs(x,y);       
22         if(temp>max)        //max保存由该点所能到达之处能吃到的最大奶酪数
23 
24            max=temp;
25      }
26   value[sx][sy]=map[sx][sy]+max;      //得到由该点出发所能吃到的最大奶酪数，保存在value里
27   return value[sx][sy];
28 }
29 
30 int main()
31 {
32   int i,j;
33   while(scanf("%d%d",&n,&k)!=EOF)
34   {
35     if(n==-1&&k==-1)
36        break;
37     memset(value,-1,sizeof(value));    //初始化数组(不能为0)
38     for(i=0;i<n;i++)
39       for(j=0;j<n;j++)
40         scanf("%d",&map[i][j]);
41      printf("%d\n",dfs(0,0));
42   }
43   return 0;
44 }