Submission #1162259

#	Time	Username	Problem	Language	Result	Execution time	Memory
1162259		hyakup	Rectangles (IOI19_rect)	C++20	72 / 100	3688 ms	1114112 KiB

rect

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

const int inf = 1e9 + 10;
const int maxn = 2500;

int l[maxn][maxn], r[maxn][maxn], u[maxn][maxn], d[maxn][maxn];

class Segment_Tree{
	struct Node{
		int l, r, u, d; Node( int l = -inf, int r = inf, int u = -inf, int d = inf ) : l(l), r(r), u(u), d(d) {}
		Node operator + ( Node n ){
			return Node( max( l, n.l ), min( r, n.r ), max( u, n.u ), min( d, n.d ) );
		}
	};
	vector<Node> seg;

	Node query( int pos, int ini, int fim, int ki, int kf ){
		if( ki > fim || ini > kf ) return seg[0];
		if( ki <= ini && fim <= kf ) return seg[pos];
		int l = 2*pos, r = 2*pos + 1, mid = ( ini + fim )/2;
		return query( l, ini, mid, ki, kf ) + query( r, mid + 1, fim, ki, kf );
	}

	void build( int pos, int ini, int fim, int id, int t ){
		if( ini == fim ){
			if( t ) seg[pos] = Node( l[id][ini], r[id][ini], u[id][ini], d[id][ini] );
			else seg[pos] = Node( l[ini][id], r[ini][id], u[ini][id], d[ini][id] );
			return;
		}
		int l = 2*pos, r = 2*pos + 1, mid = ( ini + fim )/2;
		build( l, ini, mid, id, t ); build( r, mid + 1, fim, id, t );
		seg[pos] = seg[l] + seg[r];
	}

public:
	int query( int l, int r, int t ){
		Node x = query( 1, 0, maxn, l, r );

		if( t == 0 ) return x.u;
		if( t == 1 ) return x.r;
		if( t == 2 ) return x.d;
		return x.l;
	}

	void build( int id, int t ){ build( 1, 0, maxn, id, t ); }

	Segment_Tree() { seg.resize(4*maxn); }
};
Segment_Tree linha[maxn], coluna[maxn];


long long count_rectangles( vector<vector<int>> mat ) {
	int n = mat.size(), m = mat[0].size();

	for( int i = 0; i < n; i++ ){
		stack<pair<int, pair<int, int>>> pilha;
		pilha.push({ inf, make_pair(-1, -1) });
		for( int j = 0; j < m; j++ ){
			l[i][j] = -1; r[i][j] = m;
			while( pilha.top().first < mat[i][j] ){
				auto [a, b] = pilha.top().second;
				r[a][b] = j;
				pilha.pop();
			}
			auto [a, b] = pilha.top().second;
			l[i][j] = b;
			pilha.push({ mat[i][j], make_pair( i, j ) });
		}
    for( int j = 0; j < m; j++ ) if( l[i][j] != -1 && mat[i][j] == mat[i][l[i][j]] ) r[i][l[i][j]] = j;
	}

	for( int j = 0; j < m; j++ ){
		stack<pair<int, pair<int, int>>> pilha;
		pilha.push({ inf, make_pair(-1, -1) });
		for( int i = 0; i < n; i++ ){
			u[i][j] = -1; d[i][j] = n;
			while( pilha.top().first < mat[i][j] ){
				auto [a, b] = pilha.top().second;
				d[a][b] = i;
				pilha.pop();
			}
			auto [a, b] = pilha.top().second;
			u[i][j] = a;
			pilha.push({ mat[i][j], make_pair( i, j ) });
		}

    for( int i = 0; i < n; i++ ) if( u[i][j] != -1 && mat[i][j] == mat[u[i][j]][j] ) d[u[i][j]][j] = i;
	}

	for( int i = 0; i < n; i++ ) linha[i].build( i, 1 );
	for( int j = 0; j < m; j++ ) coluna[j].build( j, 0 );

	for( int i = 0; i < n; i++ ) for( int j = 0; j < m; j++ ){
		if( l[i][j] != -1 && mat[i][j] == mat[i][l[i][j]] ) l[i][j] = l[i][l[i][j]];
		if( u[i][j] != -1 && mat[i][j] == mat[u[i][j]][j] ) u[i][j] = u[u[i][j]][j];
	}

	for( int i = n - 1; i >= 0; i-- ) for( int j = m - 1; j >= 0; j-- ){
		if( r[i][j] != m && mat[i][j] == mat[i][r[i][j]] ) r[i][j] = r[i][r[i][j]];
		if( d[i][j] != n && mat[i][j] == mat[d[i][j]][j] ) d[i][j] = d[d[i][j]][j];
	}

	set<tuple<int, int, int, int>> s;

	for( int i = 1; i < n - 1; i++ ) for( int j = 1; j < m - 1; j++ ){

		if( l[i][j] == -1 || r[i][j] == m || u[i][j] == -1 || d[i][j] == n ) continue;

		if( linha[u[i][j]].query( l[i][j] + 1, r[i][j] - 1, 2) < d[i][j] ) continue;
		if( linha[d[i][j]].query( l[i][j] + 1, r[i][j] - 1, 0) > u[i][j] ) continue;

		if( coluna[l[i][j]].query( u[i][j] + 1, d[i][j] - 1, 1) < r[i][j] ) continue;
		if( coluna[r[i][j]].query( u[i][j] + 1, d[i][j] - 1, 3) > l[i][j] ) continue;

		s.insert(make_tuple( l[i][j], r[i][j], u[i][j], d[i][j] ) );
	}

	return s.size();
}

• 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