239.cpp

/**
 *    author:   vulkan
 *    created:  20.04.2020 08:55:15 PM
**/
#include <bits/stdc++.h>

using namespace std;

void insert_elt(deque<int> &deq, vector<int> &arr, int i) {
    while (not deq.empty() and arr[deq.back()] <= arr[i]) {
        deq.pop_back();
    }

    deq.push_back(i);
}

void delete_idx(deque<int> &deq, int i) {
    while (not deq.empty() and deq.front() <= i) {
        deq.pop_front();
    }
}

vector<int> maxSlidingWindow(vector<int> &arr, int k) {
    int n = arr.size();
    deque<int> deq;
    for (int i = 0; i <= k - 2; ++i) {
        insert_elt(deq, arr, i);
    }

    vector<int> ans;
    for (int i = k - 1, j = 0; i <= n - 1; ++i, ++j) {
        insert_elt(deq, arr, i);
        ans.push_back(arr[deq.front()]);
        delete_idx(deq, j);
    }

    return ans;
}

int main(int argc, char const *argv[]) {
    int n;
    cin >> n;
    vector<int> arr(n);
    for (int i = 0; i <= n - 1; ++i) {
        cin >> arr[i];
    }
    int k;
    cin >> k;

    vector<int> ans = maxSlidingWindow(arr, k);
    for (int x : ans) {
        cout << x << ' ';
    }

    return 0;
}