Submission #766793

#	Time	Username	Problem	Language	Result	Execution time	Memory
766793		t6twotwo	Rectangles (IOI19_rect)	C++17	59 / 100	945 ms	1048576 KiB

rect

#include "rect.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int lg[2501];
struct sparse_table {
    int n, e;
    int (*f)(int, int);
    vector<vector<int>> st;
    sparse_table() {
    }
    sparse_table(vector<int> &a, int (*_f)(int, int), int _e) : n(a.size()), f(_f), e(_e) {
        st = vector(n, vector<int>(lg[n] + 1, e));
        for (int i = 0; i < n; i++) {
            st[i][0] = a[i];
        }
        for (int j = 0; j < lg[n]; j++) {
            for (int i = 0; i + (2 << j) <= n; i++) {
                st[i][j + 1] = f(st[i][j], st[i + (1 << j)][j]);
            }
        }
    }
    int query(int l, int r) {
        if (l == r) {
            return e;
        }
        int k = lg[r - l];
        return f(st[l][k], st[r - (1 << k)][k]);
    }
};
int fmin(int x, int y) {
    return min(x, y);
}
int fmax(int x, int y) {
    return max(x, y);
}
ll count_rectangles(vector<vector<int>> a) {
    for (int i = 2; i <= 2500; i++) {
        lg[i] = lg[i / 2] + 1;
    }
    int n = a.size();
    int m = a[0].size();
    bool subtask6 = 1;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (a[i][j] > 1) {
                subtask6 = 0;
            }
        }
    }
    vector<int> stk;
    int L[n][m], R[n][m], U[n][m], D[n][m];
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            while (!stk.empty() && a[i][stk.back()] < a[i][j]) {
                stk.pop_back();
            }
            L[i][j] = stk.empty() ? -1 : stk.back();
            stk.push_back(j);
        }
        stk.clear();
        for (int j = m - 1; j >= 0; j--) {
            while (!stk.empty() && a[i][stk.back()] < a[i][j]) {
                stk.pop_back();
            }
            R[i][j] = stk.empty() ? m : stk.back();
            stk.push_back(j);
        }
        stk.clear();
    }
    for (int j = 0; j < m; j++) {
        for (int i = 0; i < n; i++) {
            while (!stk.empty() && a[stk.back()][j] < a[i][j]) {
                stk.pop_back();
            }
            U[i][j] = stk.empty() ? -1 : stk.back();
            stk.push_back(i);
        }
        stk.clear();
        for (int i = n - 1; i >= 0; i--) {
            while (!stk.empty() && a[stk.back()][j] < a[i][j]) {
                stk.pop_back();
            }
            D[i][j] = stk.empty() ? n : stk.back();
            stk.push_back(i);
        }
        stk.clear();
    }
    sparse_table SL[m], SR[m], SU[n], SD[n];
    for (int i = 0; i < n; i++) {
        vector<int> u(m), d(m);
        for (int j = 0; j < m; j++) {
            u[j] = U[i][j];
            d[j] = D[i][j];
        }
        SU[i] = sparse_table(u, fmax, -1);
        SD[i] = sparse_table(d, fmin, n);
    }
    for (int i = 0; i < m; i++) {
        vector<int> l(n), r(n);
        for (int j = 0; j < n; j++) {
            l[j] = L[j][i];
            r[j] = R[j][i];
        }
        SL[i] = sparse_table(l, fmax, -1);
        SR[i] = sparse_table(r, fmin, m);
    }
    auto check = [&](int x1, int y1, int x2, int y2) -> int {
        if (x1 > x2 || y1 > y2) {
            return 0;
        }
        if (SD[x1 - 1].query(y1, y2 + 1) <= x2) {
            return 0;
        }
        if (SU[x2 + 1].query(y1, y2 + 1) >= x1) {
            return 0;
        }
        if (SR[y1 - 1].query(x1, x2 + 1) <= y2) {
            return 0;
        }
        if (SL[y2 + 1].query(x1, x2 + 1) >= y1) {
            return 0;
        }
        return 1;
    };
    int ans = 0;
    if (subtask6) {
        for (int i = 1; i < n - 1; i++) {
            for (int j = 1; j < m - 1; j++) {
                if (a[i][j] == 0 && a[i - 1][j] == 1 && a[i][j - 1] == 1) {
                    if (D[i - 1][j] != n && R[i][j - 1] != m) {
                        ans += check(i, j, D[i - 1][j] - 1, R[i][j - 1] - 1);
                    }
                }
            }
        }
        return ans;
    }
    vector<int> T[n][m];
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (U[i][j] != -1) {
                T[U[i][j]][j].push_back(i);
            }
        }
    }
    for (int i = 1; i < n - 1; i++) {
        for (int j = 1; j < m - 1; j++) {
            int y = R[i][j - 1] - 1;
            if (y != m - 1) {
                int x = D[i - 1][j] - 1;
                if (x != n - 1) {
                    ans += check(i, j, x, y);
                }
                for (int k : T[i - 1][j]) {
                    if (a[i - 1][j] != a[k][j]) {
                        ans += check(i, j, k - 1, y);
                    }
                }
            }
            y = L[i][j + 1] + 1;
            if (y != 0 && a[i][j + 1] != a[i][y - 1]) {
                int x = D[i - 1][j] - 1;
                if (x != n - 1) {
                    ans += check(i, y, x, j);
                }
                for (int k : T[i - 1][j]) {
                    if (a[i - 1][j] != a[k][j]) {
                        ans += check(i, y, k - 1, j);
                    }
                }
            }
        }
    }
    return ans;
}

Compilation message (stderr)

rect.cpp: In constructor 'sparse_table::sparse_table(std::vector<int>&, int (*)(int, int), int)':
rect.cpp:8:11: warning: 'sparse_table::f' will be initialized after [-Wreorder]
    8 |     int (*f)(int, int);
      |           ^
rect.cpp:7:12: warning:   'int sparse_table::e' [-Wreorder]
    7 |     int n, e;
      |            ^
rect.cpp:12:5: warning:   when initialized here [-Wreorder]
   12 |     sparse_table(vector<int> &a, int (*_f)(int, int), int _e) : n(a.size()), f(_f), e(_e) {
      |     ^~~~~~~~~~~~

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