洛谷 P1434 [SHOI2002]滑雪

 1 #include<cstdio>
 2 #include<iostream>
 3 using namespace std;
 4 
 5 const int maxn = 1005;
 6 
 7 int g[maxn][maxn], ans[maxn][maxn];
 8 int f[4] = {1, 0, -1, 0};
 9 int f1[4] = {0, -1, 0, 1};
10 int r, c, p;
11 
12 inline int dfs(int x, int y){
13     if(ans[x][y]) return ans[x][y];
14     int t = 1;
15     for(int i = 0; i <= 3; i++){
16         int nx = x + f[i];
17         int ny = y + f1[i];
18         if(nx >= 1 && ny >= 1 && nx <= r && ny <= c && g[x][y] > g[nx][ny])//是否越界
19             t = max(dfs(nx, ny) + 1, t);//包括自身
20     }
21     ans[x][y] = t;//保存
22     return ans[x][y];//返回
23 }
24         
25 int main(){
26     scanf("%d%d", &r, &c);
27     for(int i = 1; i <= r; i++){
28         for(int j = 1; j <= c; j++){
29             scanf("%d", &g[i][j]);
30         }
31     }
32     for(int i = 1; i <= r; i++){
33         for(int j = 1; j <= c; j++){
34             ans[i][j] = dfs(i, j);
35             p = max(p, ans[i][j]);//取最大
36         }
37     }
38     printf("%d\n", p);
39     return 0;
40 }