题目链接：
PKU:http://poj.org/problem?id=3923
HDU:http://acm.hdu.edu.cn/showproblem.php?pid=2487
Description
......................... ....AAAAAAAAAAAAA........ ....A...........A........ ....A...........A........ ....A...........A........ ....AAAAAAAAAAAAA........ ......................... Fig-1 ......................... ....AAAAAAAAAAAAA........ ....A...........A........ ....A.......BBBBBBBBBB... ....A.......B........B... ....AAAAAAAAB........B... ............BBBBBBBBBB... ......................... Fig-2 .......................... ....AAAAAAAAAAAAA......... ....A...........A......... ....A.......BBBBBBBBBB.... ....A.......B........BCCC. ....AAAAAAAAB........B..C. .......C....BBBBBBBBBB..C. .......CCCCCCCCCCCCCCCCCC. .......................... Fig-3
Input
Output
Sample Input
9 26 .......................... ....AAAAAAAAAAAAA......... ....A...........A......... ....A.......BBBBBBBBBB.... ....A.......B........BCCC. ....AAAAAAAAB........B..C. .......C....BBBBBBBBBB..C. .......CCCCCCCCCCCCCCCCCC. .......................... 7 25 ......................... ....DDDDDDDDDDDDD........ ....D...........D........ ....D...........D........ ....D...........D..AAA... ....DDDDDDDDDDDDD..A.A... ...................AAA... 0 0
Sample Output
B AD
Source
PS:注意：
7 25
...BBBBBBBBBBBBBBB.......
...BDDDDDDDDDDDDDB.......
...BDAAAAAAAAAAADB.......
...BDA.........ADB.......
...BDAAAAAAAAAAADB.......
...BDDDDDDDDDDDDDB.......
...BBBBBBBBBBBBBBB.......
6 6
AAABBB
A.AB.B
AAABBB
CCCDDD
C.CD.D
CCCDDD
代码如下：
#include<cstdio>
#include<cstring>
const int maxn = 217;
char mp[maxn][maxn];
int vis[maxn];
int n,m;
int ok(int a,int b)
{
int i, j;
for(i = b; i <= m; i++)
{
if(mp[a][i]!=mp[a][b])
break;
}
i--;
for(j = a+1; j <= n; j++) //行
{
for(int k = b; k <= i; k++)//列
{
if(k==b||k==i)//边缘不相同
{
if(mp[j][k]!=mp[a][b])
return 0;
}
else if(mp[j][k]!='.')//底边
{
for(int l = b; l <= i; l++)
{
if(mp[j][l]!=mp[a][b])
return 0;
}
return 1;
}
}
}
return 0;
}
int main()
{
int i,j;
while(~scanf("%d%d",&n,&m))
{
if(n==0 && m == 0)
break;
memset(vis,0,sizeof vis);
for(int i = 0; i < n; i++)
{
scanf("%s",mp[i]);
}
for(int i = 0; i < n; i++)
{
for(int j = 0; j < m; j++)
{
if(mp[i][j]!='.'&&vis[mp[i][j]-'A']==0)
{
vis[mp[i][j]-'A']=1;
if(ok(i,j))
vis[mp[i][j]-'A']=2;
}
}
}
int flag=1;
for(int i = 0; i < 26; i++)
{
if(vis[i] == 2)
{
if(flag)
printf("%c",i+'A');
else
printf(" %c",i+'A');
}
}
puts("");
}
}
POJ 3923 & HDU 2487 Ugly Windows（模拟）
原文：http://blog.csdn.net/u012860063/article/details/40154845