Submission #576291

#	Time	Username	Problem	Language	Result	Execution time	Memory
576291		mmonteiro	Martian DNA (BOI18_dna)	C++17	100 / 100	121 ms	4520 KiB

dna

#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>
#include <iomanip>

int main(){

    int n, k, r;

    std::cin >> n >> k >> r;

    std::vector<int> nucleobase(n);
    std::vector<int> frequency(k);

    for(int i = 0; i < n; ++i) {
        std::cin >> nucleobase[i];
    }

    for(int i = 0; i < r; ++i) {
        int x, f;
        std::cin >> x >> f;
        frequency[x] += f;
    }

    auto add = [&](int x, std::vector<int> &frequency_aux, int &qtd_ok) {
        frequency_aux[x]++;
        if(frequency_aux[x] == frequency[x] and frequency[x] > 0) {
            qtd_ok++;
        }
    };

    auto sub = [&](int x, std::vector<int> &frequency_aux, int &qtd_ok) {
        if(frequency_aux[x] == frequency[x] and frequency[x] > 0) {
            qtd_ok--;
        }
        frequency_aux[x]--;
    };

    auto check = [&](int window_size) {
        std::vector<int> frequency_aux(k);
        int qtd_ok = 0;
        for(int i = 0; i < window_size; ++i) {
            add(nucleobase[i], frequency_aux, qtd_ok);
        }
        if(qtd_ok == r) {
            return true;
        }
        for(int i = window_size; i < n; ++i) {
            sub(nucleobase[i - window_size], frequency_aux, qtd_ok);
            add(nucleobase[i], frequency_aux, qtd_ok);
            if(qtd_ok == r) {
                return true;
            }
        }
        return false;
    };

    int lo = 0, hi = n, ans = -1;

    while(lo <= hi) {
        int middle = (lo + hi) / 2;
        if(check(middle)) {
            hi = middle - 1;
            ans = middle;
        } else {
            lo = middle + 1;
        }
    }

    if(ans == -1) {
        std::cout << "impossible\n";
    } else {
        std::cout << ans << '\n';
    }

    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 24 / 24
• Subtask 3: 28 / 28
• Subtask 4: 32 / 32