Submission #439344

#	Time	Username	Problem	Language	Result	Execution time	Memory
439344		Sorting	Rectangles (IOI19_rect)	C++17	0 / 100	894 ms	135720 KiB

rect

#include "rect.h"
#include <bits/stdc++.h>
#pragma GCC optimize("O3")

using namespace std;
typedef long long ll;

const int N = 2500 + 3;

vector<vector<int>> a;
int n, m;
int u[N][N], d[N][N], l[N][N], r[N][N];

void init(){
    stack<int> st;
    for(int j = 0; j < m; ++j){
        for(int i = 0; i < n; ++i){
            while(!st.empty() && a[i][j] > a[st.top()][j]){
                d[st.top()][j] = i;
                st.pop();
            }
            st.push(i);
        }
        while(!st.empty()){
            d[st.top()][j] = n;
            st.pop();
        }
        for(int i = n - 1; i >= 0; --i){
            while(!st.empty() && a[i][j] > a[st.top()][j]){
                u[st.top()][j] = i;
                st.pop();
            }
            st.push(i);
        }
        while(!st.empty()){
            u[st.top()][j] = -1;
            st.pop();
        }
    }

    for(int i = 0; i < n; ++i){
        for(int j = 0; j < m; ++j){
            while(!st.empty() && a[i][j] > a[i][st.top()]){
                r[i][st.top()] = j;
                st.pop();
            }
            st.push(j);
        }
        while(!st.empty()){
            r[i][st.top()] = m;
            st.pop();
        }
        for(int j = n - 1; j >= 0; --j){
            while(!st.empty() && a[i][j] > a[i][st.top()]){
                l[i][st.top()] = j;
                st.pop();
            }
            st.push(j);
        }
        while(!st.empty()){
            l[i][st.top()] = -1;
            st.pop();
        }
    }
}

bool check(int x1, int y1, int x2, int y2){
    for(int i = x1; i <= x2; ++i)
        for(int j = y1; j <= y2; ++j)
            if(a[i][j] >= a[x1 - 1][j] || a[i][j] >= a[x2 + 1][j] || a[i][j] >= a[i][y1 - 1] || a[i][j] >= a[i][y2 + 1])
                return false;
    return true; 
}

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

    init();

    ll ans = 0;
    vector<array<int, 4>> v;
    for(int x = 1; x < n - 1; ++x)
        for(int y = 1; y < m - 1; ++y)
            v.push_back({u[x][y] + 1, l[x][y] + 1, d[x][y] - 1, r[x][y] - 1});
    sort(v.begin(), v.end());
    v.resize(unique(v.begin(), v.end()) - v.begin());

    for(auto [x1, y1, x2, y2]: v){
        if(x1 <= 0 || y1 <= 0 || x2 >= n - 1 || y2 >= m - 1) continue;
        //cout << x1 << " " << y1 << " " << x2 << " " << y2 << endl;
        ans += check(x1, y1, x2, y2); 
    }
    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