Submission #529518

#	Time	Username	Problem	Language	Result	Execution time	Memory
529518		zxcvbnm	trapezoid (balkan11_trapezoid)	C++14	0 / 100	86 ms	5348 KiB

trapezoid

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<array<int, 4>> a(n);
    for(auto& i : a) {
        for(auto& j : i) {
            cin >> j;
        }
    }

    auto cmp = [](const auto& l, const auto& r) {
        return min(l[1], l[3]) < min(r[1], r[3]);
    };

    auto ok = [&](int i, int j) {
        return a[j][0] > a[i][1] && a[j][2] > a[i][3];
    };

    sort(a.begin(), a.end(), cmp);
//    for(auto& i : a) {
//        for(auto& j : i) {
//            cout << j << " ";
//        }
//        cout << "\n";
//    }

//    bool can[n][n];
//    memset(can, false, sizeof can);
//
//    for(int i = 0; i < n; i++) {
//        for(int j = i+1; j < n; j++) {
//            can[i][j] = can[j][i] = ok(i, j);
//        }
//    }

    vector<int> dp(n, 1);
    vector<int> mx(n, 1);
    for(int i = 0; i < n; i++) {
        int l = 0, r = i-1, ans = -1;
        while(l <= r) {
            int mid = (l + r) / 2;
            if (ok(mid, i)) {
                ans = mid;
                l = mid + 1;
            }
            else {
                r = mid - 1;
            }
        }

        if (ans == -1) continue;
        dp[i] = dp[i] + mx[ans];
        mx[i] = max(mx[i-1], dp[i]);
    }

    cout << mx[n-1] << "\n";
    return 0;
}

• Subtask 1: 0 / 100