Submission #824750

#	Time	Username	Problem	Language	Result	Execution time	Memory
824750		tomruk	Rectangles (IOI19_rect)	C++17	100 / 100	2317 ms	805412 KiB

rect

#include "rect.h"
#include <bits/stdc++.h>
#define N 2505
using namespace std;
struct BIT2D{
	vector<vector<int>> bit;
	int n;
	BIT2D(){
		n = N;
		bit.assign(N,vector<int>(N,0));
	}
	void upd(int x,int y,int val){
		for(;x < n;x += x & -x){
			for(int tmp = y;tmp < n;tmp += tmp & -tmp){
				bit[x][tmp] += val;
			}
		}
	}
	int get(int x,int y){
		int ret = 0;
		for(;x > 0;x -= x & -x){
			for(int tmp = y;tmp > 0;tmp -= tmp & -tmp){
				ret += bit[x][tmp];
			}
		}
		return ret;
	}
};
vector<pair<int,int>> dwn[N][N];
vector<pair<int,int>> rght[N][N];
long long count_rectangles(vector<vector<int>> a){
	long long ans = 0;
	int n = a.size();
	int m = a[0].size();
	for(int i = m-1;i>=0;i--){
		vector<int> nxt(n + 5,n);
		stack<int> st;
		st.push(n-1);
		for(int j = n-2;j>=0;j--){
			while(st.size() && a[st.top()][i] <= a[j][i])
				st.pop();
			if(st.size())
				nxt[j] = st.top();
			st.push(j);
			if(a[j][i] <= a[j+1][i])
				continue;
			for(int c = nxt[j + 1];c < n;c = nxt[c]){
				auto x = lower_bound(rght[j][i+1].begin(),rght[j][i+1].end(),make_pair(c,0));
				rght[j][i].push_back({c,1});
				if(x != rght[j][i+1].end() && x->first == c){
					rght[j][i].back().second += x->second;
				}
				if(a[j][i] <= a[c][i])
					break;
			}
		}
	}
	int cnt = 0;
	BIT2D t;
	for(int i = n-1;i>0;i--){
		vector<int> nxt(m + 5,m);
		stack<int> st;
		st.push(m-1);
		for(int j = m-2;j>=0;j--){
			while(st.size() && a[i][st.top()] <= a[i][j])
				st.pop();
			if(st.size())
				nxt[j] = st.top();
			st.push(j);
			if(a[i][j] <= a[i][j+1])
				continue;
			// cout << "HEY" << ' ' << i << ' ' << j << endl;
			// cout << "ASDASD" << ans << endl;
			for(auto u:rght[i-1][j+1]){
				t.upd(u.first + 1,m-(u.second + j + 1) + 1,1);
				// cout << u.first + 1 << ' ' << m-(u.second + j + 1) + 1 << endl;
			}
			// cout << "HEY" << ' ' << i << ' ' << j << endl;
			for(int c = nxt[j + 1];c < m;c = nxt[c]){
				auto x = lower_bound(dwn[i+1][j].begin(),dwn[i+1][j].end(),make_pair(c,0));
				dwn[i][j].push_back({c,1});
				if(x != dwn[i+1][j].end() && x->first == c){
					dwn[i][j].back().second += x->second;
				}
				// cout << i + dwn[i][j].back().second + 1 << endl;
				// cout << c << endl;
				ans += t.get(i + dwn[i][j].back().second + 1,m - c + 1);
				// cout << i + dwn[i][j].back().second + 1 << ' ' <<  m - c + 1 << endl;
				// for(int d = i + 1;d <= i + dwn[i][j][c];d++){
				// 	ans += (j + 1 + rght[i-1][j+1][d]) >= c; 
				// }
				if(a[i][j] <= a[i][c])
					break;
			}
			for(auto u:rght[i-1][j+1]){
				t.upd(u.first + 1,m-(u.second + j + 1) + 1,-1);
			}
			// cout << "ASDASD" << ans << endl;	
		}
	}
	assert(cnt <= n * m);
	return ans;
}

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