Submission #1047499

#	Time	Username	Problem	Language	Result	Execution time	Memory
1047499		fuad27	Rectangles (IOI19_rect)	C++17	72 / 100	5031 ms	963924 KiB

rect

#include "rect.h"
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3")
const int N = 2510;
int n,m;
vector<pair<int,int>> gdr[N];
vector<pair<int,int>> gdc[N];

struct Side {
	int r1, r2, c1, c2;
};
vector<pair<short,short>> hsides[N][N];
vector<pair<short,short>> vsides[N][N];


int fen[N];
void upd(int at, int add) {
	at++;
	while(at) {
		fen[at]+=add;
		at-=at&(-at);
	}
}
int qry(int at) {
	at++;
	int sum=0;
	while(at<N) {
		sum+=fen[at];
		at+=at&(-at);
	}
	return sum;
}
			

long long count_rectangles(std::vector<std::vector<int> > a) {
	n = a.size();
	m = a[0].size();
	for(int i = 0;i<n;i++) {
		vector<int> stk;
		for(int j = 0;j<m;j++) {
			while(stk.size() and a[i][stk.back()] < a[i][j]){
				stk.pop_back();
			}
			if(stk.size()) {
				gdr[i].push_back({stk.back(), j});
			}
			stk.push_back(j);
		}
		stk.clear();
		for(int j = m-1;j>=0;j--) {
			while(stk.size() and a[i][stk.back()] < a[i][j])stk.pop_back();
			if(stk.size()) {
				if(a[i][j] != a[i][stk.back()])
					gdr[i].push_back({j, stk.back()});
			}
			stk.push_back(j);
		}
		sort(gdr[i].begin(), gdr[i].end());
	}
	for(int i = 0;i<m;i++) {
		vector<int> stk;
		for(int j = 0;j<n;j++) {
			while(stk.size() and a[stk.back()][i] < a[j][i]){
				stk.pop_back();
			}
			if(stk.size()) {
				gdc[i].push_back({stk.back(), j});
			}
			stk.push_back(j);
		}
		stk.clear();
		for(int j = n-1;j>=0;j--) {
			while(stk.size() and a[stk.back()][i] < a[j][i])stk.pop_back();
			if(stk.size()) {
				gdc[i].push_back({j, stk.back()});
			}
			stk.push_back(j);
		}
		sort(gdc[i].begin(), gdc[i].end());
		gdc[i].erase(unique(gdc[i].begin(), gdc[i].end()), gdc[i].end());
	}
	Side seg;
	for(int i = 0;i<n;i++) {
		for(auto pr:gdr[i]) {

			if(pr.first +1 == pr.second)continue;
			if(i!=n-1 and (*lower_bound(gdr[i+1].begin(), gdr[i+1].end(), pr)) == pr)continue;
			seg.r1 = pr.first;
			seg.r2 = pr.second;
			seg.c2 = i;
			for(int j = i;j>=0;j--){
				auto it = (lower_bound(gdr[j].begin(), gdr[j].end(), pr));
				if(it == gdr[j].end())break;
				if((*it)!=pr)break;
				seg.c1=j;
			}
			seg.c1--;
			seg.c2++;
			seg.c1=max(seg.c1, 0);
			seg.c2=min(seg.c2, n-1);
			for(int j = seg.c1;j<=seg.c2;j++) {
				hsides[j][seg.r2].push_back(pair<int,int>(seg.c1, seg.r1));
			}
		}
	}
	for(int i = 0;i<m;i++) {
		for(auto pr:gdc[i]) {
			if(pr.first +1 == pr.second)continue;
			if(i!=m-1 and (*lower_bound(gdc[i+1].begin(), gdc[i+1].end(), pr)) == pr)continue;
			seg.r1 = pr.first;
			seg.r2 = pr.second;
			seg.c2 = i;
			for(int j = i;j>=0;j--){
				auto it = (lower_bound(gdc[j].begin(), gdc[j].end(), pr));
				if(it == gdc[j].end())break;
				if((*it)!=pr)break;
				seg.c1=j;
			}
			seg.c1--;
			seg.c2++;
			seg.c1=max(seg.c1, 0);
			seg.c2=min(seg.c2, m-1);
			for(int j = seg.c1;j<=seg.c2;j++) {
				vsides[seg.r2][j].push_back(pair<int,int>(seg.r1, seg.c1));
			}
		}
	}


	long long ans=0;
	for(int i = 0;i<n;i++) {
		for(int j = 0;j<m;j++) {
			int tmp=0;
			sort(vsides[i][j].begin(), vsides[i][j].end());
			sort(hsides[i][j].begin(), hsides[i][j].end());
			int p1 = 0;
			for(auto k:vsides[i][j]) {
				while(p1 < (int)hsides[i][j].size() and hsides[i][j][p1].first <= k.first) {
					upd(hsides[i][j][p1++].second, 1);
				}
				ans+=qry(k.second);
			}
			while(p1 < (int)hsides[i][j].size()) {
				upd(hsides[i][j][p1++].second, 1);
			}
			for(auto k:hsides[i][j]) {
				upd(k.second, -1);
			}
		}
	}
	return ans;
}

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:134:8: warning: unused variable 'tmp' [-Wunused-variable]
  134 |    int tmp=0;
      |        ^~~
rect.cpp:98:10: warning: 'seg.Side::c1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   98 |    seg.c1--;
      |    ~~~~~~^~

• 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: 0 / 28