제출 #755560

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
755560		MilosMilutinovic	송신탑 (IOI22_towers)	C++17	0 / 100	736 ms	19600 KiB

towers

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

vector<vector<int>> vec;

namespace sparse {
    int n;
    vector<int> logs;
    vector<vector<int>> st;
    void build(vector<int> h) {
        n = (int) h.size();
        logs.resize(n + 1);
        st.resize(n);
        for (int i = 0; i < n; i++) {
            st[i].resize(20);
            st[i][0] = h[i];
        }
        for (int j = 1; j < 20; j++)
            for (int i = 0; i + (1 << j) <= n; i++)
                st[i][j] = max(st[i][j - 1], st[i + (1 << (j - 1))][j - 1]);
        for (int i = 2; i <= n; i++) logs[i] = logs[i >> 1] + 1;
    }
    int query(int l, int r) {
        int k = logs[r - l + 1];
        return max(st[l][k], st[r - (1 << k) + 1][k]);
    }
};

void init(int n, vector<int> h) {
    vector<int> l_id(n), r_id(n);
    vector<int> stk;
    for (int i = 0; i < n; i++) {
        while (!stk.empty() && h[i] < h[stk.back()]) {
            stk.pop_back();
        }
        l_id[i] = (stk.empty() ? -1 : stk.back());
        stk.push_back(i);
    }
    stk.clear();
    for (int i = n - 1; i >= 0; i--) {
        while (!stk.empty() && h[i] < h[stk.back()]) {
            stk.pop_back();
        }
        r_id[i] = (stk.empty() ? -1 : stk.back());
        stk.push_back(i);
    }
    sparse::build(h);
    vector<int> order(n);
    iota(order.begin(), order.end(), 0);
    sort(order.begin(), order.end(), [&](int i, int j) { return h[i] < h[j]; });
    for (int _i = 1; _i < n; _i++) {
        int i = order[_i];
        int d = 2e9;
        if (l_id[i] != -1 && l_id[i] != i - 1)
            d = min(d, sparse::query(l_id[i], i) - h[i]);
        if (r_id[i] != -1 && r_id[i] != i + 1)
            d = min(d, sparse::query(i, r_id[i]) - h[i]);
//        printf("%d %d\n", i + 1, d);
        vec.push_back({d, i, l_id[i], r_id[i]});
    }
    sort(vec.begin(), vec.end());
}

int find_first(int x) {
    int l = 0, r = vec.size() - 1, p = -1;
    while (l <= r) {
        int mid = l + r >> 1;
        if (vec[mid][0] <= x)
            l = mid + 1, p = mid;
        else
            r = mid - 1;
    }
    return p + 1;
}

int max_towers(int l, int r, int d) {
    return find_first(d) + 1;
}


/*
7 1
10 20 60 40 50 30 70
0 6 17
*/

컴파일 시 표준 에러 (stderr) 메시지

towers.cpp: In function 'int find_first(int)':
towers.cpp:68:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   68 |         int mid = l + r >> 1;
      |                   ~~^~~

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