Submission #146790

#	Time	Username	Problem	Language	Result	Execution time	Memory
146790		gs14004	Rectangles (IOI19_rect)	C++17	10 / 100	5031 ms	280384 KiB

rect

#include "rect.h"
#include <bits/stdc++.h>
#define sz(v) ((int)(v).size())
using namespace std;
using pi = pair<int, int>;
using lint = long long;
const int MAXN = 2505;

struct bit{
	int tree[MAXN];
	void add(int x, int v){
		for(int i=x; i<MAXN; i+=i&-i) tree[i] += v;
	}
	int query(int x){
		int ret = 0;
		for(int i=x; i; i-=i&-i) ret += tree[i];
		return ret;
	}
}bit;

struct strip{ int x, s, e, up; };

void proc(vector<strip> &v){
	sort(v.begin(), v.end(), [&](const strip &a, const strip &b){
		if(a.s != b.s) return a.s < b.s;
		if(a.e != b.e) return a.e < b.e;
		if(a.x != b.x) return a.x < b.x;
	});
	v.resize(unique(v.begin(), v.end(), [&](const strip &a, const strip &b){
		return a.s == b.s && a.e == b.e && a.x == b.x;
	}) - v.begin());
	for(int i=1; i<v.size(); i++){
		if(pi(v[i-1].s, v[i-1].e) == pi(v[i].s, v[i].e) && v[i-1].x + 1 == v[i].x) v[i].up = v[i-1].up + 1;
	}
}

int L[MAXN], R[MAXN];
lint count_rectangles(vector<vector<int>> a){
	vector<strip> rdir, ldir;
	int n = sz(a);
	int m = sz(a[0]);
	vector<int> stk;
	for(int i=1; i<n-1; i++){
		memset(L, -1, sizeof(L));
		memset(R, -1, sizeof(R));
		for(int j=0; j<m; j++){
			while(!stk.empty() && a[i][stk.back()] <= a[i][j]) stk.pop_back();
			if(stk.size()) L[j] = stk.back();
			stk.push_back(j);
		}
		stk.clear();
		for(int j=m-1; j>=0; j--){
			while(!stk.empty() && a[i][stk.back()] <= a[i][j]) stk.pop_back();
			if(stk.size()) R[j] = stk.back();
			stk.push_back(j);
		}
		stk.clear();
		for(int j=0; j<m; j++){
			if(L[j] != -1 && R[j] != -1){
				rdir.push_back({i, L[j], R[j], 1});
			}
		}
	}
	for(int i=1; i<m-1; i++){
		memset(L, -1, sizeof(L));
		memset(R, -1, sizeof(R));
		for(int j=0; j<n; j++){
			while(!stk.empty() && a[stk.back()][i] <= a[j][i]) stk.pop_back();
			if(stk.size()) L[j] = stk.back();
			stk.push_back(j);
		}
		stk.clear();
		for(int j=n-1; j>=0; j--){
			while(!stk.empty() && a[stk.back()][i] <= a[j][i]) stk.pop_back();
			if(stk.size()) R[j] = stk.back();
			stk.push_back(j);
		}
		stk.clear();
		for(int j=0; j<n; j++){
			if(L[j] != -1 && R[j] != -1){
				ldir.push_back({i, L[j], R[j], 1});
			}
		}
	}
	proc(ldir);
	proc(rdir);
	sort(ldir.begin(), ldir.end(), [&](const strip &a, const strip &b){
		return pi(a.e, a.x) < pi(b.e, b.x);
	});
	sort(rdir.begin(), rdir.end(), [&](const strip &a, const strip &b){
		return pi(a.x, a.e) < pi(b.x, b.e);
	});
	int p1 = 0, p2 = 0;
	lint ret = 0;
	for(int i=2; i<n; i++){
		for(int j=2; j<m; j++){
			vector<pi> punk1, punk2;
			while(p1 < sz(rdir) && pi(rdir[p1].x + 1, rdir[p1].e) == pi(i, j)){
				punk1.emplace_back(j - rdir[p1].s - 1, rdir[p1].up);
				p1++;
			}
			while(p2 < sz(ldir) && pi(ldir[p2].e, ldir[p2].x + 1) == pi(i, j)){
				punk2.emplace_back(ldir[p2].up, i - ldir[p2].s - 1);
				p2++;
			}
			sort(punk1.begin(), punk1.end());
			sort(punk2.begin(), punk2.end());
			int p3 = 0;
			for(auto &y : punk2){
				while(p3 < sz(punk1) && punk1[p3].first <= y.first) bit.add(punk1[p3++].second, +1);
				ret += p3 - bit.query(y.second - 1);
			}
			for(int i=0; i<p3; i++) bit.add(punk1[i].second, -1);
		}
	}
	return ret;
}

Compilation message (stderr)

rect.cpp: In function 'void proc(std::vector<strip>&)':
rect.cpp:32:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=1; i<v.size(); i++){
               ~^~~~~~~~~
rect.cpp: In lambda function:
rect.cpp:28:2: warning: control reaches end of non-void function [-Wreturn-type]
  });
  ^

• 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