제출 #422989

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
422989		donentseto	Rectangles (IOI19_rect)	C++14	23 / 100	1991 ms	747320 KiB

rect

#include <bits/stdc++.h>
using namespace std;

const int maxn = 2505;
int n, m;
vector <short> rows [maxn][maxn], cols [maxn][maxn];
vector <pair <short, short> > rows1 [maxn][maxn], cols1 [maxn][maxn];
short fenwick [maxn];

long long count_rectangles (vector <vector <int> > a){
	
	n = a.size ();
	m = a [0].size ();
	if (n < 3 || m < 3) return 0;
	long long ans = 0;

	stack <short> s;
	for (int i = n - 2; i > 0; i --){
		s.push (0);
		for (int j = 1; j < m; j ++){
			while (!s.empty ()){
				if (s.top () != j - 1) rows [s.top () + 1][j - 1].push_back (i);
				if (a [i][s.top ()] < a [i][j]) s.pop ();
				else{
					if (a [i][s.top ()] == a [i][j]) s.pop ();
					break;
				}
			}
			s.push (j);
		}
	}
	while (!s.empty()) s.pop ();
	for (int i = m - 2; i > 0; i --){
		s.push (0);
		for (int j = 1; j < n; j ++){
			while (!s.empty ()){
				if (s.top () != j - 1) cols [s.top () + 1][j - 1].push_back (i);
				if (a [s.top ()][i] < a [j][i]) s.pop ();
				else{
					if (a [s.top ()][i] == a [j][i]) s.pop ();
					break;
				}
			}
			s.push (j);
		}
	}

	int sz, last, x;
	for (int i = 1; i < m - 1; i ++){
		for (int j = i; j < m - 1; j ++){
			sz = rows [i][j].size ();
			if (sz == 0) continue;
			last = rows [i][j][0];
			cols1 [rows [i][j][0]][i].push_back ({j, last});
			for (x = 1; x < sz; x ++){
				if (rows [i][j][x] < rows [i][j][x - 1] - 1) last = rows [i][j][x];
				cols1 [rows [i][j][x]][i].push_back ({j, last});
			}
		}
	}
	for (int i = 1; i < n - 1; i ++){
		for (int j = i; j < n - 1; j ++){
			sz = cols [i][j].size ();
			if (sz == 0) continue;
			last = cols [i][j][0];
			rows1 [i][cols [i][j][0]].push_back ({last, j});
			for (x = 1; x < sz; x ++){
				if (cols [i][j][x] < cols [i][j][x - 1] - 1) last = cols [i][j][x];
				rows1 [i][cols [i][j][x]].push_back ({last, j});
			}
		}
	}

	int sz_r, sz_c, r, c;
	for (int i = 1; i < n - 1; i ++){
		for (int j = 1; j < m - 1; j ++){
			sz_r = rows1 [i][j].size (), sz_c = cols1 [i][j].size ();
			sort (rows1 [i][j].begin (), rows1 [i][j].end ());
			r = sz_r - 1;
			for (c = sz_c - 1; c >= 0; c --){
				while (r >= 0 && rows1 [i][j][r].first >= cols1 [i][j][c].first){
					x = rows1 [i][j][r].second;
					while (x <= n){
						fenwick [x] ++;
						x += x & -x;
					}
					r --;
				}
				x = cols1 [i][j][c].second;
				while (x > 0){
					ans += fenwick [x];
					x -= x & -x;
				}
			}
			while (r < sz_r - 1){
				r ++;
				x = rows1 [i][j][r].second;
				while (x <= n){
					fenwick [x] --;
					x += x & -x;
				}
			}
		}
	}
	
	return ans;

}

//long long bruteforce (vector <vector <int> > a){

	//n = a.size ();
	//m = a [0].size ();
	//if (n < 3 || m < 3) return 0;
	//long long ans = 0;
	
	//for (int u = 1; u < n - 1; u ++){
		//for (int d = u; d < n - 1; d ++){
			//for (int l = 1; l < m - 1; l ++){
				//for (int r = l; r < m - 1; r ++){
					//bool flag = 1;
					//for (int i = u; i <= d; i ++){
						//for (int j = l; j <= r; j ++){
							//if (a [i][j] >= a [u - 1][j] || a [i][j] >= a [d + 1][j] || a [i][j] >= a [i][l - 1] || a [i][j] >= a [i][r + 1]){
								//flag = 0;
								//break;
							//}
						//}
						//if (!flag) break;
					//}
					//ans += flag;
				//}
			//}
		//}
	//}

	//return ans;

//}

//mt19937 mt (5172893);

//int main (){

	//while (1){
		//n = mt () % 5 + 1;
		//m = mt () % 5 + 1;
		//vector <vector <int> > a (n);
		//for (int i = 0; i < n; i ++){
			//for (int j = 0; j < m; j ++){
				//a [i].push_back (mt () % 10);
			//}
		//}
		//long long ans1 = count_rectangles (a);
		//long long ans2 = bruteforce (a);
		//if (ans1 != ans2){
			//cout << "damn\n";
			//cout << ans1 << ' ' << ans2 << '\n';
			//cout << n << ' ' << m << '\n';
			//for (auto v : a){
				//for (auto i : v) cout << i << ' ';
				//cout << '\n';
			//}
			//return 0;
		//}
		//cout << "ok\n";
		//for (int i = 0; i <= 30; i ++){
			//for (int j = 0; j <= 30; j ++){
				//rows [i][j].clear ();
				//cols [i][j].clear ();
				//rows1 [i][j].clear ();
				//cols1 [i][j].clear ();
			//}
		//}
	//}

//}

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