제출 #1221398

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1221398		totoro	Radio Towers (IOI22_towers)	C++20	11 / 100	4065 ms	13476 KiB

towers

#include "towers.h"

#include <map>
#include <vector>

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) {
    std::vector<int> dp(n + 10);
    dp[l] = 1;
    int max = 1;
    for (int i = l + 1; i <= r; ++i) {
        dp[i] = 1;
        for (int j = l; j < i; ++j) {
            if (can_communicate(j, i, d)) dp[i] = std::max(dp[i], dp[j] + 1);
        }
        max = std::max(max, dp[i]);
    }
    return max;
}

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