HDU 4618 Palindrome Sub-Array(DP)

题目链接

我还是图样啊....比赛的时候没敢暴力去搜...

 1 #include <cstdio>
 2 #include <cstdlib>
 3 #include <cstring>
 4 #include <map>
 5 #include <ctime>
 6 #include <cmath>
 7 using namespace std;
 8 #define LL __int64
 9 char dp[301][301][301];
10 int p[301][301];
11 int n,m;
12 int dfs(int x,int y,int step)
13 {
14     int i,j,k;
15     if(step == 1)
16     return 1;
17     else if(step == 0)
18     return 1;
19     if(x > n||y > m)
20     return 2;
21     if(dp[x][y][step] == 1)
22     return 1;
23     else if(dp[x][y][step] == 2)
24     return 2;
25     int flag = 1;
26     for(i = x,j = x+step-1,k = 1;k <= step/2&&flag;i ++,j --,k ++)
27     {
28         if(p[i][y] == p[j][y]&&p[i][y] == p[i][y+step-1])
29         ;
30         else
31         flag = 0;
32     }
33     for(i = y,j = y+step-1,k = 1;k <= step/2&&flag;i ++,j --,k ++)
34     {
35         if(p[x][i] == p[x][j]&&p[x][i] == p[x+step-1][i])
36         ;
37         else
38         flag = 0;
39     }
40     if(flag == 0)
41     {
42         dp[x][y][step] = 2;
43         return 2;
44     }
45     else if(flag)
46     {
47         return dp[x+1][y+1][step-2] = dfs(x+1,y+1,step-2);
48     }
49     return 0;
50 }
51 int main()
52 {
53     int t,i,j,k,flag;
54     scanf("%d",&t);
55     while(t--)
56     {
57         scanf("%d%d",&n,&m);
58         memset(dp,0,sizeof(dp));
59         for(i = 1;i <= n;i ++)
60         {
61             for(j = 1;j <= m;j ++)
62             {
63                 scanf("%d",&p[i][j]);
64             }
65         }
66         flag = 1;
67         for(i = min(n,m);i >= 2&&flag;i --)
68         {
69             for(j = 1;j <= n-i+1&&flag;j ++)
70             {
71                 for(k = 1;k <= m-i+1&&flag;k ++)
72                 {
73                     if(dfs(j,k,i) == 1)
74                     flag = 0;
75                 }
76             }
77             if(!flag) break;
78         }
79         printf("%d
",i);
80     }
81     return 0;
82 }
原文地址:https://www.cnblogs.com/naix-x/p/3215215.html