Submission #1043322

#	Time	Username	Problem	Language	Result	Execution time	Memory
1043322		idas	Rectangles (IOI19_rect)	C++17	0 / 100	1 ms	604 KiB

rect

#include "rect.h"
#include "bits/stdc++.h"
#define FOR(i, begin, end) for(int i=(begin); i<(end); i++)
#define s second
#define f first

using namespace std;
typedef pair<int, int> pii;

const int MxN=2510;
int n, m, a[MxN][MxN], cn[MxN][MxN];
pii par[MxN][MxN];

pii fnd(int i, int j) {
	if(par[i][j]==pii({i,j})) {
		return {i,j};
	}
	pii ret=fnd(par[i][j].f, par[i][j].s);
	return par[i][j]=ret;
}

void mrg(int i, int j, int x, int y) {
	pii a=fnd(i, j), b=fnd(x, y);
	if(a.f==b.f && a.s==b.s) return;
	cn[b.f][b.s]+=cn[a.f][a.s];
	par[a.f][a.s]=b;
}

bool st_node(int i, int j, int in) {
	if(in==0) return a[i][j]==0 && a[i][j-1]==1 && a[i-1][j]==1 && a[i+1][j]==1;
	return a[i][j]==0 && a[i-1][j]==1 && a[i][j-1]==1 && a[i][j+1]==1;
}

bool nd_node(int i, int j, int in) {
	if(in==0) return a[i][j]==0 && a[i-1][j]==1 && a[i+1][j]==1 && a[i][j+1]==1;
	return a[i][j]==0 && a[i+1][j]==1 && a[i][j-1]==1 && a[i][j+1]==1;
}

bool mid_node(int i, int j, int in) {
	if(in==0) return a[i][j]==0 && a[i-1][j]==1 && a[i+1][j]==1;
	return a[i][j]==0 && a[i][j-1]==1 && a[i][j+1]==1;
}

bool sqr(int i, int j) {
	return a[i][j]==0 && a[i+1][j]==1 && a[i-1][j]==1 && a[i][j-1]==1 && a[i][j+1]==1;
}

bool corn(int i, int j) {
	int sm=a[i-1][j]+a[i+1][j]+a[i][j-1]+a[i][j+1];
	if(sm!=2) return false;

	if(a[i][j]==0 && a[i-1][j]==1 && a[i][j-1]==1) return true;
	if(a[i][j]==0 && a[i-1][j]==1 && a[i][j+1]==1) return true;
	if(a[i][j]==0 && a[i+1][j]==1 && a[i][j-1]==1) return true;
	if(a[i][j]==0 && a[i+1][j]==1 && a[i][j+1]==1) return true;
	return false;
}

long long count_rectangles(std::vector<std::vector<int> > A) {
	n=A.size(); m=A[0].size();
	FOR(i, 0, n) FOR(j, 0, m) a[i][j]=A[i][j];

	int ans=0;
	FOR(i, 1, n-1) FOR(j, 1, m-1) if(sqr(i, j)) ans++;

	FOR(i, 1, n-1) {
		bool started=false;
		FOR(j, 1, m-1) {
			if(st_node(i, j, 0)) {
				started=true;
			}
			else if(nd_node(i, j, 0)) {
				if(started) ans++;
			}
			else if(!mid_node(i, j, 0)) {
				started=false;
			}
		}
	}

	FOR(j, 1, m-1) {
		bool started=false;
		FOR(i, 1, n-1) {
			if(st_node(i, j, 1)) {
				started=true;
			}
			else if(nd_node(i, j, 1)) {
				if(started) ans++;
			}
			else if(!mid_node(i, j, 1)) {
				started=false;
			}
		}
	}

	FOR(i, 1, n-1) {
		FOR(j, 1, m-1) {
			par[i][j]={i,j};

			if(corn(i, j)) cn[i][j]++;

			if(a[i-1][j]==0) mrg(i, j, i-1, j);
			if(a[i][j-1]==0) mrg(i, j, i, j-1);
		}
	}

	map<pii, int> mp;
	FOR(i, 1, n-1) {
		FOR(j, 1, m-1) {
			auto [fst, snd]=fnd(i, j);
			mp[{fst,snd}]=cn[fst][snd];
		}
	}

	for(auto it : mp) {
		if(it.s==4) ans++;
	}

	return ans;
}

• 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