Submission #625458

#	Time	Username	Problem	Language	Result	Execution time	Memory
625458		model_code	Radio Towers (IOI22_towers)	C++17	0 / 100	1135 ms	4124 KiB

towers

// incorrect/solution-full-interval-wa.cpp
#ifndef ATCODER_INTERNAL_BITOP_HPP
#define ATCODER_INTERNAL_BITOP_HPP 1

#ifdef _MSC_VER
#include <intrin.h>
#endif

namespace atcoder {

namespace internal {

// @param n `0 <= n`
// @return minimum non-negative `x` s.t. `n <= 2**x`
int ceil_pow2(int n) {
    int x = 0;
    while ((1U << x) < (unsigned int)(n)) x++;
    return x;
}

// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
constexpr int bsf_constexpr(unsigned int n) {
    int x = 0;
    while (!(n & (1 << x))) x++;
    return x;
}

// @param n `1 <= n`
// @return minimum non-negative `x` s.t. `(n & (1 << x)) != 0`
int bsf(unsigned int n) {
#ifdef _MSC_VER
    unsigned long index;
    _BitScanForward(&index, n);
    return index;
#else
    return __builtin_ctz(n);
#endif
}

}  // namespace internal

}  // namespace atcoder

#endif  // ATCODER_INTERNAL_BITOP_HPP

#ifndef ATCODER_SEGTREE_HPP
#define ATCODER_SEGTREE_HPP 1

#include <algorithm>
#include <cassert>
#include <vector>

namespace atcoder {

template <class S, S (*op)(S, S), S (*e)()> struct segtree {
  public:
    segtree() : segtree(0) {}
    explicit segtree(int n) : segtree(std::vector<S>(n, e())) {}
    explicit segtree(const std::vector<S>& v) : _n(int(v.size())) {
        log = internal::ceil_pow2(_n);
        size = 1 << log;
        d = std::vector<S>(2 * size, e());
        for (int i = 0; i < _n; i++) d[size + i] = v[i];
        for (int i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set(int p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) const {
        assert(0 <= p && p < _n);
        return d[p + size];
    }

    S prod(int l, int r) const {
        assert(0 <= l && l <= r && r <= _n);
        S sml = e(), smr = e();
        l += size;
        r += size;

        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }
        return op(sml, smr);
    }

    S all_prod() const { return d[1]; }

    template <bool (*f)(S)> int max_right(int l) const {
        return max_right(l, [](S x) { return f(x); });
    }
    template <class F> int max_right(int l, F f) const {
        assert(0 <= l && l <= _n);
        assert(f(e()));
        if (l == _n) return _n;
        l += size;
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(op(sm, d[l]))) {
                while (l < size) {
                    l = (2 * l);
                    if (f(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*f)(S)> int min_left(int r) const {
        return min_left(r, [](S x) { return f(x); });
    }
    template <class F> int min_left(int r, F f) const {
        assert(0 <= r && r <= _n);
        assert(f(e()));
        if (r == 0) return 0;
        r += size;
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(op(d[r], sm))) {
                while (r < size) {
                    r = (2 * r + 1);
                    if (f(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    int _n, size, log;
    std::vector<S> d;

    void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
};

}  // namespace atcoder

#endif  // ATCODER_SEGTREE_HPP

#include "towers.h"

#include <bits/stdc++.h>
using namespace std;

int Max(int a, int b) {
  return max(a, b);
}

int Min(int a, int b) {
  return min(a, b);
}

int Large() {
  return INT_MAX >> 1;
}

int Small() {
  return -Large();
}

typedef atcoder::segtree<int, Max, Small> MaxSegtree;
typedef atcoder::segtree<int, Min, Large> MinSegtree;

int N;
vector<int> H;
MaxSegtree max_st;
MinSegtree min_st;
vector<int> maxDs;

void init(int _N, std::vector<int> _H) {
  N = _N;
  H = _H;
  max_st = MaxSegtree(H);
  min_st = MinSegtree(H);
  for (int i = 0; i < N; ++i) {
    int lower_height_left = min_st.min_left(
        i, [&] (int h) { return h >= H[i]; }) - 1;
    int lower_height_right = min_st.max_right(
        i + 1, [&] (int h) { return h >= H[i]; });
    int maxD = INT_MAX;
    if (lower_height_left >= 0) {
      maxD = min(maxD, max_st.prod(lower_height_left + 1, i) - H[i]);
    }
    if (lower_height_right < N) {
      maxD = min(maxD, max_st.prod(i + 1, lower_height_right) - H[i]);
    }
    maxDs.push_back(maxD);
  }
  sort(maxDs.begin(), maxDs.end());
}

int max_towers(int L, int R, int D) {
  // WA: Towers with maxD = D should be counted as well.
  return N - (upper_bound(maxDs.begin(), maxDs.end(), D) - maxDs.begin());
}

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