Submission #692492

#	Time	Username	Problem	Language	Result	Execution time	Memory
692492		sharaelong	Rectangles (IOI19_rect)	C++17	72 / 100	5045 ms	818224 KiB

rect

#include "rect.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;

const int MAX_N = 2500 + 1;

vector<int> row_conds[MAX_N][MAX_N];
vector<int> col_conds[MAX_N][MAX_N];
pii row_range[MAX_N][MAX_N]; // in the same row
pii col_range[MAX_N][MAX_N]; // in the same col

ll count_rectangles(vector<vector<int>> a) {
	int n = a.size();
    int m = a[0].size();
    memset(row_range, -1, sizeof row_range);
    memset(col_range, -1, sizeof col_range);
    
    for (int i=1; i+1<n; ++i) {
        vector<pii> st;
        for (int j=0; j<m; ++j) {
            while (!st.empty() && st.back().first < a[i][j]) {
                row_range[i][st.back().second].second = j-1;
                st.pop_back();
            }
            st.push_back({ a[i][j], j });
        }
        st.clear();
        for (int j=m-1; j>=0; --j) {
            while (!st.empty() && st.back().first < a[i][j]) {
                row_range[i][st.back().second].first = j+1;
                st.pop_back();
            }
            st.push_back({ a[i][j], j });
        }
    }
    for (int i=1; i+1<m; ++i) {
        vector<pii> st;
        for (int j=0; j<n; ++j) {
            while (!st.empty() && st.back().first < a[j][i]) {
                col_range[st.back().second][i].second = j-1;
                st.pop_back();
            }
            st.push_back({ a[j][i], j });
        }
        st.clear();
        for (int j=n-1; j>=0; --j) {
            while (!st.empty() && st.back().first < a[j][i]) {
                col_range[st.back().second][i].first = j+1;
                st.pop_back();
            }
            st.push_back({ a[j][i], j });
        }
    }

    for (int i=1; i+1<n; ++i) {
        for (int j=1; j+1<m; ++j) {
            auto[a, b] = row_range[i][j];
            if (a != -1 && b != -1) row_conds[a][b].push_back(i);
        }
    }
    for (int j=1; j+1<m; ++j) {
        for (int i=1; i+1<n; ++i) {
            auto[c, d] = col_range[i][j];
            if (c != -1 && d != -1) col_conds[c][d].push_back(j);
        }
    }

    for (int i=0; i<MAX_N; ++i) {
        for (int j=i; j<MAX_N; ++j) {
            row_conds[i][j].erase(unique(row_conds[i][j].begin(), row_conds[i][j].end()), row_conds[i][j].end());
            col_conds[i][j].erase(unique(col_conds[i][j].begin(), col_conds[i][j].end()), col_conds[i][j].end());
            // cout << i << ' ' << j << endl; 
            // for (int x: row_conds[i][j]) cout << x << ' ';
            // cout << endl;
            // for (int x: col_conds[i][j]) cout << x << ' ';
            // cout << endl;
        }
    }

    set<tuple<int, int, int, int>> ans;
    for (int i=1; i+1<n; ++i) {
        for (int j=1; j+1<m; ++j) {
            auto[a, b] = row_range[i][j];
            auto[c, d] = col_range[i][j];
            if (a != -1 && b != -1 && c != -1 && d != -1) {
                auto row_lb = lower_bound(row_conds[a][b].begin(), row_conds[a][b].end(), c);
                auto row_ub = lower_bound(row_conds[a][b].begin(), row_conds[a][b].end(), d);
                auto col_lb = lower_bound(col_conds[c][d].begin(), col_conds[c][d].end(), a);
                auto col_ub = lower_bound(col_conds[c][d].begin(), col_conds[c][d].end(), b);
                // cout << i << ' ' << j << ' ' << *row_lb << ' ' << *row_ub << ' ' << *col_lb << ' ' << *col_ub << endl;
                if (*row_lb == c && *row_ub == d && row_ub-row_lb == d-c
                    && *col_lb == a && *col_ub == b && col_ub-col_lb == b-a) {
                    ans.insert({ a, b, c, d });
                }
            }
        }
    }
    return ans.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