一道单调栈好题
#include<cstdio>
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<algorithm>
#define gc getchar()
using namespace std;
const int N=1e3+10;
inline void qr(int &x)
{
x=0;char c=gc;
while(c<'0'||c>'9')c=gc;
while(c>='0'&&c<='9'){x=x*10+(c^48);c=gc;}
}
void qw(int x)
{
if(x<0)x=-x,putchar('-');
if(x/10)qw(x/10);
putchar(x%10+48);
}
char mp[N][N],s[N][N];int n,m;
inline void change(int i)//1--->a 2--->b 3--->c
{
if(i==1)
{
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++)
if(mp[i][j]=='w'||mp[i][j]=='y'||mp[i][j]=='z')
s[i][j]='a';
else
s[i][j]=mp[i][j];
}
else if(i==2)
{
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++)
if(mp[i][j]=='w'||mp[i][j]=='x'||mp[i][j]=='z')
s[i][j]='b';
else
s[i][j]=mp[i][j];
}
else
{
for(int i=1;i<=n;i++)
for(int j=1;j<=m;j++)
if(mp[i][j]=='x'||mp[i][j]=='y'||mp[i][j]=='z')
s[i][j]='c';
else
s[i][j]=mp[i][j];
}
}
int h[N],l[N],r[N];
inline int solve(char c)
{
int ans=0;
for(int i=1;i<=n;i++)
{
for(int j=1;j<=m;j++){l[j]=j,r[j]=j;if(s[i][j]==c)h[j]++;else h[j]=0;}
r[m+1]=m+1;h[m+1]=h[0]=-1e9;
for(int j=2;j<=m;j++)
while(h[j]<=h[l[j]-1])l[j]=l[l[j]-1];
for(int j=m-1;j>=1;j--)
while(h[j]<=h[r[j]+1])r[j]=r[r[j]+1];
for(int i=1;i<=m;i++)
ans=max(ans,(r[i]-l[i]+1)*h[i]);
}
return ans;
}
int main()
{
while(~scanf("%d%d",&n,&m))
{
int ans=0;
for(int i=1;i<=n;i++)scanf("%s",mp[i]+1);
change(1);memset(h,0,sizeof(h));
ans=max(ans,solve('a'));
change(2);memset(h,0,sizeof(h));
ans=max(ans,solve('b'));
change(3);memset(h,0,sizeof(h));
ans=max(ans,solve('c'));
qw(ans);puts("");
}
return 0;
}
最后一次更新于2019-11-14
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