Luogu1169 [ZJOI2017]棋盤製作

繼續懸線法

CODE:

#include<iostream>
#include<cstdio>
using namespace std;
int n, m, f[1001][1001], ans2, ans1, l[1001][1001], r[1001][1001];
int h[1001][1001];
int main(){
    scanf("%d%d", &n, &m);
    for(int i=1; i<=n; i++)
        for(int j=1; j<=m; j++){
			scanf("%d", &f[i][j]);
			l[i][j]=r[i][j]=j;
			h[i][j]=1;
        }
    for(int i=1; i<=n; i++){
        for(int j=2; j<=m; j++)
            if(f[i][j]!=f[i][j-1]) l[i][j]=l[i][j-1];
        for(int j=m-1; j>0; j--)
            if(f[i][j]!=f[i][j+1]) r[i][j]=r[i][j+1];
    }
    for(int i=1; i<=m+1; i++)
        r[0][i]=m+1;
    for(int i=1; i<=n; i++)
        for(int j=1; j<=m; j++)
            if(i>1&&f[i][j]!=f[i-1][j]){
                h[i][j]=h[i-1][j]+1;
                l[i][j]=max(l[i][j], l[i-1][j]);
                r[i][j]=min(r[i][j], r[i-1][j]);
                int zfx=min(r[i][j]-l[i][j]+1, h[i][j]);
                ans1=max(ans1, (r[i][j]-l[i][j]+1)*h[i][j]);
                ans2=max(ans2, zfx*zfx);
            }
    printf("%d\n%d", ans2, ans1);
    return 0;
}