Submission #709749

#	Time	Username	Problem	Language	Result	Execution time	Memory
709749		KoD	Radio Towers (IOI22_towers)	C++17	23 / 100	4049 ms	11332 KiB

towers

#include "towers.h"

#include <vector>
#include <iostream>
#include <algorithm>
#include <utility>
#include <numeric>
#include <limits>
#include <iterator>
#include <tuple>

namespace kod {

using std::vector;
using std::cerr;
using std::endl;
using std::begin;
using std::end;
using std::pair;
using std::tuple;

template <class F>
struct make_fixed : private F {
    explicit make_fixed(F&& f) : F(std::forward<F>(f)) {}
    template <class... Args> decltype(auto) operator()(Args&&... args) const {
        return F::operator()(*this, std::forward<Args>(args)...);
    }
};

int N;
vector<int> H;

int solve(int L, int R, int D) {
    const int M = R - L + 1;
    const auto A = H.begin() + L;
    vector<int> par(M, -1), stack;
    vector<vector<int>> child(M);
    for (int i = 0; i < M; ++i) {
        int j = -1;
        while (!stack.empty() and A[stack.back()] < A[i]) {
            j = stack.back();
            stack.pop_back();
        }
        if (j != -1) par[j] = i;
        if (!stack.empty()) par[i] = stack.back();
        stack.push_back(i);
    }
    int root = -1;
    for (int i = 0; i < M; ++i) {
        if (par[i] == -1) root = i;
        else child[par[i]].push_back(i);
    }
    const int ret = make_fixed([&](auto&& dfs, const int u) -> pair<int, int>  {
        int sum = 0, min = A[u];
        for (const int v : child[u]) {
            const auto [s, mi] = dfs(v);
            sum += std::max(s, A[u] - mi >= D ? 1 : 0);
            min = std::min(min, mi);
        }
        return {sum, min};
    })(root).first;
    return std::max(ret, 1);
}

}

void init(int N, std::vector<int> H) {
    kod::N = N;
    kod::H = H;
    // kod::init();
}

int max_towers(int L, int R, int D) {
    return kod::solve(L, R, D);
}

• Subtask 1: 0 / 4
• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 17
• Subtask 6: 0 / 19
• Subtask 7: 0 / 23