Submission #266713

#	Time	Username	Problem	Language	Result	Execution time	Memory
266713		dennisstar	Rectangles (IOI19_rect)	C++17	10 / 100	3068 ms	235208 KiB

rect

#include <bits/stdc++.h>
#include "rect.h"
#define eb emplace_back
using namespace std;
using tii=tuple<int, int, int>;

int N, M, A;
vector<tii> H, V;

long long count_rectangles(vector<vector<int>> a) {
	N=a.size(); M=a[0].size();
	vector<vector<int>> l, r, u, d;
	for (int i=0; i<N; i++)
		l.eb(vector<int>(M, -1));
	r=u=d=l;

	for (int i=0; i<N; i++) {
		vector<int> st;
		for (int j=0; j<M; j++) {
			while (st.size()&&a[i][st.back()]<a[i][j]) st.pop_back();
			if (st.size()) H.eb(st.back(), j, i);
			st.eb(j);
		}
		st.clear();
		for (int j=M-1; j>=0; j--) {
			while (st.size()&&a[i][st.back()]<a[i][j]) st.pop_back();
			if (st.size()) H.eb(j, st.back(), i);
			st.eb(j);
		}
		st.clear();
		for (int j=0; j<M; j++) {
			while (st.size()&&a[i][st.back()]<=a[i][j]) st.pop_back();
			if (st.size()) l[i][j]=st.back();
			st.eb(j);
		}
		st.clear();
		for (int j=M-1; j>=0; j--) {
			while (st.size()&&a[i][st.back()]<=a[i][j]) st.pop_back();
			if (st.size()) r[i][j]=st.back();
			st.eb(j);
		}
	}

	for (int j=0; j<M; j++) {
		vector<int> st;
		for (int i=0; i<N; i++) {
			while (st.size()&&a[st.back()][j]<a[i][j]) st.pop_back();
			if (st.size()) V.eb(st.back(), i, j);
			st.eb(i);
		}
		st.clear();
		for (int i=N-1; i>=0; i--) {
			while (st.size()&&a[st.back()][j]<a[i][j]) st.pop_back();
			if (st.size()) V.eb(i, st.back(), j);
			st.eb(i);
		}
		st.clear();
		for (int i=0; i<N; i++) {
			while (st.size()&&a[st.back()][j]<=a[i][j]) st.pop_back();
			if (st.size()) u[i][j]=st.back();
			st.eb(i);
		}
		st.clear();
		for (int i=N-1; i>=0; i--) {
			while (st.size()&&a[st.back()][j]<=a[i][j]) st.pop_back();
			if (st.size()) d[i][j]=st.back();
			st.eb(i);
		}
	}

	sort(H.begin(), H.end());
	H.resize(unique(H.begin(), H.end())-H.begin());
	
	sort(V.begin(), V.end());
	V.resize(unique(V.begin(), V.end())-V.begin());

	for (int i=1; i<N-1; i++) for (int j=1; j<M-1; j++) {
		int L=l[i][j], R=r[i][j], U=u[i][j], D=d[i][j];
		if (L==-1||R==-1||U==-1||D==-1) continue;

		int b1=lower_bound(H.begin(), H.end(), tii(L, R, U+1))-H.begin();
		int b2=lower_bound(H.begin(), H.end(), tii(L, R, D-1))-H.begin();
		if (b1>=H.size()||tii(L, R, U+1)<H[b1]) continue;
		if (b2>=H.size()||tii(L, R, D-1)<H[b2]) continue;
		if (b2-b1!=D-U-2) continue;

		b1=lower_bound(V.begin(), V.end(), tii(U, D, L+1))-V.begin();
		b2=lower_bound(V.begin(), V.end(), tii(U, D, R-1))-V.begin();
		if (b1>=V.size()||tii(U, D, L+1)<V[b1]) continue;
		if (b2>=V.size()||tii(U, D, R-1)<V[b2]) continue;
		if (b2-b1!=R-L-2) continue;

		A++;
	}

	return A;
}

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:83:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::tuple<int, int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   83 |   if (b1>=H.size()||tii(L, R, U+1)<H[b1]) continue;
      |       ~~^~~~~~~~~~
rect.cpp:84:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::tuple<int, int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   84 |   if (b2>=H.size()||tii(L, R, D-1)<H[b2]) continue;
      |       ~~^~~~~~~~~~
rect.cpp:89:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::tuple<int, int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   89 |   if (b1>=V.size()||tii(U, D, L+1)<V[b1]) continue;
      |       ~~^~~~~~~~~~
rect.cpp:90:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::tuple<int, int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   90 |   if (b2>=V.size()||tii(U, D, R-1)<V[b2]) continue;
      |       ~~^~~~~~~~~~

• 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