Deque-STL C++


Problem Statement :


Double ended queue or Deque(part of C++ STL) are sequence containers with dynamic sizes that can be expanded or contracted on both ends (either its front or its back). The member functions of deque that are mainly used are:

    Deque Template:

    std::deque<value_type>

    Declaration:

    deque<int> mydeque; //Creates a double ended queue of deque of int type

    Size

    int length = mydeque.size(); //Gives the size of the deque

    Push

    mydeque.push_back(1); //Pushes element at the end
    mydeque.push_front(2); //Pushes element at the beginning

    Pop

    mydeque.pop_back(); //Pops element from the end
    mydeque.pop_front(); //Pops element from the beginning

    Empty

    mydeque.empty() //Returns a boolean value which tells whether the deque is empty or not

To know more about deque, click here

Given a set of arrays of size N and an integer K, you have to find the maximum integer for each and every contiguous subarray of size K for each of the given arrays.

Input Format

First line of input will contain the number of test cases T. For each test case, you will be given the size of array N and the size of subarray to be used K. This will be followed by the elements of the array Ai.

Constraints

  1 <=  T  <= 1000
  1 <=  N  <= 10000
  1 <=  K  <= N
  1 <=  Ai  <= 10000  , where Ai is ith  the element in the array  A.

Output Format

For each of the contiguous subarrays of size K of each array, you have to print the maximum integer.


Solution :



title-img 


                            Solution in C :

#include<bits/stdc++.h>
using namespace std;
int main(){

  int t;
  cin >> t;
  while(t--){
       int n , k , x ;
       cin >> n >> k ;

       vector<int> vec;
       for(int i =  0 ; i < n ; ++i ){
          cin >> x;
          vec.push_back(x);
       }
        int mx = 0;
        vector<int> nval;
       for(int i =  0 ; i < n ; ++i ){

                  if(i%k == 0)
                   mx = vec[i];
                else
                mx = max( mx , vec[i] );
                nval.push_back(mx);
       }
       mx = 0;
       vector<int> val;
       for(int i = n-1 ; i >= 0 ; --i ){
             if(i%k == (k-1))
               mx = vec[i];
               else
               mx = max( mx , vec[i]);
               val.push_back(mx);

       }
       for(int i = 0 ; i < vec.size()-k+1  ; ++i )
             cout << max( nval[i+k-1] , val[val.size()-i-1]) <<" ";
             cout << endl;
             }
             return 0;

}








View More Similar Problems

Merge two sorted linked lists

This challenge is part of a tutorial track by MyCodeSchool Given pointers to the heads of two sorted linked lists, merge them into a single, sorted linked list. Either head pointer may be null meaning that the corresponding list is empty. Example headA refers to 1 -> 3 -> 7 -> NULL headB refers to 1 -> 2 -> NULL The new list is 1 -> 1 -> 2 -> 3 -> 7 -> NULL. Function Description C

View Solution →

Get Node Value

This challenge is part of a tutorial track by MyCodeSchool Given a pointer to the head of a linked list and a specific position, determine the data value at that position. Count backwards from the tail node. The tail is at postion 0, its parent is at 1 and so on. Example head refers to 3 -> 2 -> 1 -> 0 -> NULL positionFromTail = 2 Each of the data values matches its distance from the t

View Solution →

Delete duplicate-value nodes from a sorted linked list

This challenge is part of a tutorial track by MyCodeSchool You are given the pointer to the head node of a sorted linked list, where the data in the nodes is in ascending order. Delete nodes and return a sorted list with each distinct value in the original list. The given head pointer may be null indicating that the list is empty. Example head refers to the first node in the list 1 -> 2 -

View Solution →

Cycle Detection

A linked list is said to contain a cycle if any node is visited more than once while traversing the list. Given a pointer to the head of a linked list, determine if it contains a cycle. If it does, return 1. Otherwise, return 0. Example head refers 1 -> 2 -> 3 -> NUL The numbers shown are the node numbers, not their data values. There is no cycle in this list so return 0. head refer

View Solution →

Find Merge Point of Two Lists

This challenge is part of a tutorial track by MyCodeSchool Given pointers to the head nodes of 2 linked lists that merge together at some point, find the node where the two lists merge. The merge point is where both lists point to the same node, i.e. they reference the same memory location. It is guaranteed that the two head nodes will be different, and neither will be NULL. If the lists share

View Solution →

Inserting a Node Into a Sorted Doubly Linked List

Given a reference to the head of a doubly-linked list and an integer ,data , create a new DoublyLinkedListNode object having data value data and insert it at the proper location to maintain the sort. Example head refers to the list 1 <-> 2 <-> 4 - > NULL. data = 3 Return a reference to the new list: 1 <-> 2 <-> 4 - > NULL , Function Description Complete the sortedInsert function

View Solution →