Submission #1047761

#	Time	Username	Problem	Language	Result	Execution time	Memory
1047761		vjudge1	Rectangles (IOI19_rect)	C++17	10 / 100	49 ms	33964 KiB

rect

#include "rect.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define pb push_back
#define ff first
#define all(x) x.begin(), x.end()
#define ss second
const int N = 2600, K = 20;
int rmq[N][K];

int get(int l, int r){
	int k = int(log2(r-l+1));
	return max(rmq[l][k], rmq[r-(1<<k)+1][k]);
}
long long count_rectangles(std::vector<std::vector<int> > a) {
	int n = a.size();
	int m = a[0].size();

	if(n < 3 || m < 3){
		return 0;
	}

	if(n == 3){
		vector<bool> good(m);
		for(int i = 1; i + 1 < m; ++i){
			if(a[1][i] < a[0][i] && a[1][i] < a[2][i]){
				good[i] = 1;
			}else good[i] = 0;
		}

		for(int i = 1; i < m; ++i) rmq[i][0] = (good[i] ? a[1][i] : INT_MAX);
		for(int j = 1; j < K; ++j){
			for(int i = 1; i + (1<<j) <= m; ++i){
				rmq[i][j] = max(rmq[i][j - 1], rmq[i+(1<<(j-1))][j-1]);
			}
		}
		int ans = 0;
		for(int i = 1; i + 1 < m; ++i){
			for(int j = i; j + 1 < m; ++j){
				if(get(i, j) < min(a[1][i - 1], a[1][j + 1]) && good[i]){
					++ans;
				}
			}
		}

		return ans;
	}
	vector<vector<int>> dp(n, vector<int>(m));
	ll ans = 0;
	for(int i = 1; i + 1 < n; ++i){
		for(int j = 1; j + 1 < m; ++j){
			if(a[i][j] == 1){
				dp[i][j] = 0;
			}else{
				dp[i][j] = dp[i - 1][j] + 1;
			}
		}
	}
	// for(int i = 0; i < n; ++i){
	// 	for(int j = 0; j < m; ++j) cout << a[i][j];
	// 	cout << '\n';
	// }
	for(int i = 1; i + 1 < n; ++i){
		int r = 1;
		for(int j = 1; j + 1 < m; ++j){
			// cout << i << ' ' << j << '\n';
			if(a[i][j] == 1) continue;
			// cout << i << ' ' << j << '\n';
			if(a[i][j - 1] != 1) continue;
			if(a[i + 1][j] != 1) continue;
			r = j;
			while(r + 1 < m && a[i][r] == 0 && a[i + 1][r] == 1) ++r;
			--r;
			if(a[i][r + 1] != 1){
				j = r;
				continue;
			}

			ll sum = 0;
			int mx = dp[i][j];
			int ok = 1;

			vector<pair<int, ll>> v;
			for(int l = j; l <= r; ++l){
				// int co = 1;
				// while(!v.empty() && v.back().first > dp[i][l]){
				// 	co += v.back().second;
				// 	sum -= v.back().first * v.back().second;
				// 	v.pop_back();
				// }
				// sum += dp[i][l] * co;
				// v.pb({dp[i][l], co});
				if(dp[i][l] != mx) ok = 0;
			}
			ans += ok;

			// cout << i << ' ' << j << ' ' << r << ' ' << ans << '\n';

			j = r;
		}
	}

	return ans;
}

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:80:7: warning: unused variable 'sum' [-Wunused-variable]
   80 |    ll sum = 0;
      |       ^~~

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