P1736-创意吃鱼法 

 1 #include <bits/stdc++.h>
 2 #define maxn 13003
 3 #define _for(i,a,b) for(int i = (a);i < b;i ++)
 4 typedef long long ll;
 5 using namespace std;
 6 inline ll read()
 7 {
 8     ll ans = 0;
 9     char ch = getchar(), last = ' ';
10     while(!isdigit(ch)) last = ch, ch = getchar();
11     while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
12     if(last == '-') ans = -ans;
13     return ans;
14 }
15 inline void write(ll x)
16 {
17     if(x < 0) x = -x, putchar('-');
18     if(x >= 10) write(x / 10);
19     putchar(x % 10 + '0');
20 }
21 int n,m;
22 int a[2503][2503];
23 int dp[2503][2503];
24 int h[2503][2503];
25 int d[2503][2503];
26 int main()
27 {
28     n = read(), m = read();
29     _for(i,1,n+1)
30         _for(j,1,m+1)
31             a[i][j] = read();
32     
33     for(int i = 1;i < n+1;i ++)
34     {
35         h[i][1] = 0;
36         for(int j = 2;j < m+1;j ++)
37         {
38             if(a[i][j-1]==0)
39                 h[i][j] = h[i][j-1]+1;
40             else
41                 h[i][j] = 0;
42         }
43     }
44 
45     for(int i = 1;i < m+1;i ++)
46     {
47         d[1][i] = 0;
48         for(int j = 2;j < n+1;j ++)
49         {
50             if(a[j-1][i]==0)
51                 d[j][i] = d[j-1][i]+1;
52             else
53                 d[j][i] = 0;
54         }
55     }
56     
57     int rnt = 0;
58     
59     _for(i,1,n+1)
60         _for(j,1,m+1)
61             if(a[i][j]==1)
62                 dp[i][j] = min(dp[i-1][j-1],min(d[i][j],h[i][j])) + 1,
63                 rnt = max(rnt,dp[i][j]);
64     
65     memset(h,0,sizeof(h));
66     memset(dp,0,sizeof(dp));
67     for(int i = 1;i < n+1;i ++)
68     {
69         h[i][m] = 0;
70         for(int j = m-1;j > 1;j --)
71         {
72             if(a[i][j+1]==0)
73                 h[i][j] = h[i][j+1]+1;
74             else
75                 h[i][j] = 0;
76         }
77     }
78     
79     _for(i,1,n+1)
80         for(int j = m;j > 0;j --)
81             if(a[i][j]==1)
82                 dp[i][j] = min(dp[i-1][j+1],min(d[i][j],h[i][j])) + 1,
83                 rnt = max(rnt,dp[i][j]);
84     
85     write(rnt);    
86     return 0;
87 }

 

posted @ 2019-08-13 16:28  Asurudo  阅读(161)  评论(0)    收藏  举报