Submission #349210

#	Time	Username	Problem	Language	Result	Execution time	Memory
349210		tengiz05	Rectangles (IOI19_rect)	C++17	50 / 100	1991 ms	100844 KiB

rect

#include "rect.h"
#ifndef EVAL
#include "grader.cpp"
#endif
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2505;
int n, m, dp[N][N];
vector<vector<int>> a;
inline bool check(int r1, int c1, int r2, int c2){
	for(int i=r1;i<=r2;i++){
		for(int j=c1;j<=c2;j++){
			int t = min(min(a[i][c1-1], a[i][c2+1]), min(a[r1-1][j], a[r2+1][j]));
			if(a[i][j] >= t)return false;
		}
	}return true;
}

int get(int x1,int y1,int x2,int y2){
	int res = dp[x2][y2];
	if(x1&&y1)res += dp[x1-1][y1-1];
	if(x1)res -= dp[x1-1][y2];
	if(y1)res -= dp[x2][y1-1];
	return res;
}


ll count_rectangles(vector<vector<int>> a){
	::a = a;
	n = a.size();
	m = a[0].size();
	ll ans = 0;
	if(n*m <= 50000){
		for(int i=1;i<n-1;i++){
			for(int j=1;j<m-1;j++){
				for(int I=i;I<n-1;I++){
					for(int J=j;J<m-1;J++){
						ans += check(i,j,I,J);
					}
				}
			}
		}return ans;
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<m;j++){
			dp[i][j] = a[i][j];
			if(j)dp[i][j] += dp[i][j-1];
		}for(int j=0;j<m;j++){
			if(i)dp[i][j] += dp[i-1][j];
		}
	}
	for(int i=1;i<n-1;i++){
		for(int j=1;j<m-1;j++){
			if(a[i][j]==1)continue;
			if(a[i][j-1]!=1 || a[i-1][j]!=1)continue;
			int x = i, y = j;
			while(x+1 < n && a[x+1][j]==0)x++;
			while(y+1 < m && a[i][y+1]==0)y++;
			if(get(i,j,x,y) == 0 && get(i-1,j,i-1,y) == y-j+1 && get(x+1,j,x+1,y) == y-j+1 && get(i,j-1,x,j-1) == x-i+1 && get(i,y+1,x,y+1) == x-i+1)ans++;
		}
	}
	return ans;
}

• Subtask 1: 8 / 8
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 0 / 22
• Subtask 5: 10 / 10
• Subtask 6: 13 / 13
• Subtask 7: 0 / 28