Submission #1221399

#	Time	Username	Problem	Language	Result	Execution time	Memory
1221399		totoro	Radio Towers (IOI22_towers)	C++20	4 / 100	299 ms	13472 KiB

towers

#include <map>
#include <vector>

#include "towers.h"

int n;
std::vector<int> heights;
std::vector<int> heightsc;
std::vector<std::vector<int>> stc;
std::map<int, int> cc;
std::vector<int> invcc;

void init(int N, std::vector<int> H) {
    n = N;
    for (int i : H) cc[i] = 0;
    int cccounter = 0;
    for (auto& [x, y] : cc) y = cccounter++, invcc.push_back(x);
    heightsc = heights = H;
    for (int& i : heightsc) i = cc[i];

    stc.push_back(heightsc);
    for (int sz = 1; sz < 20; ++sz) {
        stc.emplace_back();
        for (int i = 0; i + (1 << sz) <= N; ++i) {
            stc[sz].push_back(std::max(stc[sz - 1][i], stc[sz - 1][i + (1 << (sz - 1))]));
        }
    }
}

int rangemax(int l, int r) {
    int sz = r - l + 1;
    int log = -1;
    while (sz) sz >>= 1, ++log;
    return invcc[std::max(stc[log][l], stc[log][r - (1 << log) + 1])];
}

bool can_communicate(int x, int y, int interference) {
    return rangemax(x, y) >= std::max(heights[x], heights[y]) + interference;
}

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

• Subtask 1: 4 / 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