Submission #725165

#	Time	Username	Problem	Language	Result	Execution time	Memory
725165		dooompy	Rectangles (IOI19_rect)	C++17	100 / 100	2848 ms	595556 KiB

rect

#include "bits/stdc++.h"
#include "rect.h"

using namespace std;

void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
    cout << a << ' ', abc(b...);
}

template <typename A, typename B> istream& operator >> (istream& o, pair<A, B> &a) {
    return o >> a.first >> a.second;
}
template <typename A, typename B> ostream& operator << (ostream& o, pair<A, B> a) {
    return o << '(' << a.first << ", " << a.second << ')';
}
template <typename T> ostream& operator << (ostream& o, vector<T> a) {
    bool is = false;
    for (T i : a) {o << (is ? ' ' : '{'), is = true, o << i;}
    return o << '}';
}

#ifdef local
#define test(args...) abc("{" + string(#args) + "}", args)
#else
#define test(args...) void(0)
#endif

using ll = long long;

int lft[2505][2505];
int rht[2505][2505];
vector<pair<int, int>> interval[2505];
vector<pair<int, int>> otherrow[2505][2505];

struct segment {
    int l, r, last;

    bool operator<(segment o) const {
        return l < o.l;
    }
};

vector<segment> row[2505];

int bit[2505][2505];

void update(int id, int pos, int val) {
    for (; pos < 2505; pos += pos & -pos) {
        bit[id][pos] += val;
    }
}

int query(int id, int pos) {
    int sum = 0;
    for (; pos; pos -= pos & -pos) {
        sum += bit[id][pos];
    }

    return sum;
}

ll count_rectangles(vector<vector<int>> a) {
    int n = a.size();
    int m= a[0].size();

    if (min(n, m) <= 2) {
        return 0;
    }

    deque<int> dq;

    memset(lft, -1, sizeof(lft));
    memset(rht, -1, sizeof(rht));

    for (int i = 1; i <= n - 2; i++) {
        while (!dq.empty()) dq.pop_back();

        for (int j = 0; j < m; j++) {
            while (!dq.empty() && a[i][j] > a[i][dq.back()]) dq.pop_back();
            if (!dq.empty() && dq.back() != j-1) {
                lft[i][j] = dq.back();
                interval[i].push_back({dq.back(), j});
            }
            dq.push_back(j);
        }

        while (!dq.empty()) dq.pop_back();
        for (int j = m - 1; j >= 0; j--) {
            while (!dq.empty() && a[i][j] > a[i][dq.back()]) dq.pop_back();
            if (!dq.empty() && dq.back() != j+1) {
                rht[i][j] = dq.back();
                interval[i].push_back({j, dq.back()});
            }
            dq.push_back(j);
        }
    }

    for (int i = 1; i <= n-2; i++) {
        for (auto [l, r] : interval[i]) {
            if (lft[i][r] != l && rht[i][l] != r) continue;
            if (lft[i][r] == l) lft[i][r] = -1;
            if (rht[i][l] == r) rht[i][l] = -1;
            int nxt = i + 1;
            while (nxt <= n - 2 && (lft[nxt][r] == l || rht[nxt][l] == r)) {
                if (lft[nxt][r] == l) lft[nxt][r] = -1;
                if (rht[nxt][l] == r) rht[nxt][l] = -1;
                nxt++;
            }

            for (int j = i; j < nxt; j++) {
                row[j].push_back({l + 1, r - 1, nxt - 1});
            }
        }

        sort(row[i].begin(), row[i].end());
    }

    memset(lft,-1,sizeof(lft));
    memset(rht,-1,sizeof(rht));

    for (int i = 1; i <= m - 2; i++) {
        while (!dq.empty()) dq.pop_back();

        for (int j = 0; j < n; j++) {
            while (!dq.empty() && a[j][i] > a[dq.back()][i]) dq.pop_back();
            if (!dq.empty() && dq.back() != j-1) {
                lft[i][j] = dq.back();
                interval[i].push_back({dq.back(), j});
            }
            dq.push_back(j);
        }

        while (!dq.empty()) dq.pop_back();
        for (int j = n - 1; j >= 0; j--) {
            while (!dq.empty() && a[j][i] > a[dq.back()][i]) dq.pop_back();
            if (!dq.empty() && dq.back() != j+1) {
                rht[i][j] = dq.back();
                interval[i].push_back({j, dq.back()});
            }
            dq.push_back(j);
        }
    }

    for (int i = 1; i <= m - 2; i++) {
        for (auto [l, r] : interval[i]) {
            if (lft[i][r] != l && rht[i][l] != r) continue;
            if (lft[i][r] == l) lft[i][r] = -1;
            if (rht[i][l] == r) rht[i][l] = -1;
            int nxt = i + 1;
            while (nxt <= m - 2 && (lft[nxt][r] == l || rht[nxt][l] == r)) {
                if (lft[nxt][r] == l) lft[nxt][r] = -1;
                if (rht[nxt][l] == r) rht[nxt][l] = -1;
                nxt++;
            }

            for (int j = i; j < nxt; j++) {
                otherrow[l + 1][i].emplace_back(j, r - 1);
            }
        }
    }

    ll ans = 0;

    for (int i = 1; i <= n - 2; i++) {
        int cur = 1;
        vector<pair<int, int>> ops;
        for (auto [l, r, last] : row[i]) {
            while (cur <= l) {
                for (auto [col, lastrow] : otherrow[i][cur]) {
                    update(col, lastrow, 1);
                    ops.push_back({col, lastrow});
                }
                cur++;
            }

            ans += query(r, last);
        }

        while (!ops.empty()) {
            auto [col, lastrow] = ops.back();
            ops.pop_back();
            update(col, lastrow, -1);
        }
    }

    return ans;
}

//int main() {
//    ios_base::sync_with_stdio(0);
//    cin.tie(0); cout.tie(0);
////    freopen("", "r", stdin);
////    freopen("", "w", stdout);
//    cout << count_rectangles({{4, 8, 7, 5, 6},
//    {7, 4, 10, 3, 5},
//    {9, 7, 20, 14, 2},
//    {9, 14, 7, 3, 6},
//    {5, 7, 5, 2, 7},
//    {4, 5, 13, 5, 6}});
//}

• 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: 28 / 28