Submission #197892

#	Time	Username	Problem	Language	Result	Execution time	Memory
197892		arnold518	Rectangles (IOI19_rect)	C++14	0 / 100	5 ms	1272 KiB

rect

#pragma GCC optimize ("O3")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")

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

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int MAXN = 2500;

int N, M, A[MAXN+10][MAXN+10];
int L[MAXN+10][MAXN+10], R[MAXN+10][MAXN+10], U[MAXN+10][MAXN+10], D[MAXN+10][MAXN+10];

struct Line
{
	int y, x1, x2;
	bool operator < (const Line &p) const
	{
		if(y!=p.y) return y<p.y;
		if(x1!=p.x1) return x1<p.x1;
		return x2<p.x2;
	}

	bool operator == (const Line &p) { return y==p.y && x1==p.x1 && x2==p.x2; }
	bool operator != (const Line &p) { return !(y==p.y && x1==p.x1 && x2==p.x2); }
};

vector<Line> H, V, HB[MAXN+10], VB[MAXN+10];
int PHB[MAXN+10], PVB[MAXN+10];
int lowH[MAXN*MAXN+10], lowV[MAXN*MAXN+10];

ll count_rectangles(vector<vector<int>> _A)
{
	int i, j;

	N=_A.size(); M=_A[0].size();
	for(i=1; i<=N; i++) for(j=1; j<=M; j++) A[i][j]=_A[i-1][j-1];

	for(i=1; i<=N; i++)
	{
		vector<int> S;
		S.clear();
		for(j=1; j<=M; j++) L[i][j]=0;
		for(j=1; j<=M; j++)
		{
			while(!S.empty() && A[i][S.back()]<=A[i][j]) S.pop_back();
			if(!S.empty()) L[i][j]=S.back();
			S.push_back(j);
		}

		S.clear();
		for(j=1; j<=M; j++) R[i][j]=M+1;
		for(j=M; j>=1; j--)
		{
			while(!S.empty() && A[i][S.back()]<=A[i][j]) S.pop_back();
			if(!S.empty()) R[i][j]=S.back();
			S.push_back(j);
		}
	}
	
	for(i=1; i<=M; i++)
	{
		vector<int> S;
		S.clear();
		for(j=1; j<=N; j++) U[j][i]=0;
		for(j=1; j<=N; j++)
		{
			while(!S.empty() && A[S.back()][i]<=A[j][i]) S.pop_back();
			if(!S.empty()) U[j][i]=S.back();
			S.push_back(j);
		}

		S.clear();
		for(j=1; j<=N; j++) D[j][i]=N+1;
		for(j=N; j>=1; j--)
		{
			while(!S.empty() && A[S.back()][i]<=A[j][i]) S.pop_back();
			if(!S.empty()) D[j][i]=S.back();
			S.push_back(j);
		}
	}

	for(i=1; i<=N; i++)
	{
		for(j=1; j<=M; j++)
		{
			if(L[i][j]==0) continue;
			if(R[i][j]==M+1) continue;
			H.push_back({i, L[i][j]+1, R[i][j]-1});
		}
		for(j=1; j<=M; j++)
		{
			if(U[i][j]==0) continue;
			if(D[i][j]==N+1) continue;
			V.push_back({j, U[i][j]+1, D[i][j]-1});
		}
	}

	sort(H.begin(), H.end());
	H.erase(unique(H.begin(), H.end()), H.end());

	sort(V.begin(), V.end());
	V.erase(unique(V.begin(), V.end()), V.end());

	for(i=H.size()-1, j=H.size()-1; i>=0; i--)
	{
		lowH[i]=H[i].y;
		Line t={H[i].y+1, H[i].x1, H[i].x2};
		for(; j>=0 && t<H[j]; j--);
		if(j>=0 && t==H[j]) lowH[i]=lowH[j];
	}

	for(i=V.size()-1, j=V.size()-1; i>=0; i--)
	{
		lowV[i]=V[i].y;
		Line t={V[i].y+1, V[i].x1, V[i].x2};
		for(; j>=0 && t<V[j]; j--);
		if(j>=0 && t==V[j]) lowV[i]=lowV[j];
	}

	for(auto it : H) HB[it.y].push_back(it);
	for(auto it : V) VB[it.y].push_back(it);
	for(i=1; i<=N; i++) PHB[i]=PHB[i-1]+HB[i].size();
	for(i=1; i<=M; i++) PVB[i]=PVB[i-1]+VB[i].size();

	vector<pair<pii, pii>> ans;
	for(i=2; i<=N-1; i++) for(j=2; j<=M-1; j++)
	{
		if(L[i][j]==0) continue;
		if(R[i][j]==M+1) continue;
		if(U[i][j]==0) continue;
		if(D[i][j]==N+1) continue;

		Line tu={U[i][j]+1, L[i][j]+1, R[i][j]-1};
		Line tl={L[i][j]+1, U[i][j]+1, D[i][j]-1};

		auto it=lower_bound(HB[tu.y].begin(), HB[tu.y].end(), tu);
		auto jt=lower_bound(VB[tl.y].begin(), VB[tl.y].end(), tl);

		if(it!=HB[tu.y].end() && *it!=tu) continue;
		if(jt!=VB[tl.y].end() && *jt!=tl) continue;

		if(lowH[it-HB[tu.y].begin()+PHB[tu.y-1]]<D[i][j]-1) continue;
		if(lowV[jt-VB[tl.y].begin()+PVB[tl.y-1]]<R[i][j]-1) continue;

		ans.push_back({pii(L[i][j]+1, R[i][j]-1), pii(U[i][j]+1, D[i][j]-1)});
	}
	sort(ans.begin(), ans.end());
	ans.erase(unique(ans.begin(), ans.end()), ans.end());
	return ans.size();
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 7
• Subtask 3: 0 / 12
• Subtask 4: 0 / 22
• Subtask 5: 0 / 10
• Subtask 6: 0 / 13
• Subtask 7: 0 / 28