**Java Dequeue**

### Problem Statement :

In computer science, a double-ended queue (dequeue, often abbreviated to deque, pronounced deck) is an abstract data type that generalizes a queue, for which elements can be added to or removed from either the front (head) or back (tail). Deque interfaces can be implemented using various types of collections such as LinkedList or ArrayDeque classes. For example, deque can be declared as: Deque deque = new LinkedList<>(); or Deque deque = new ArrayDeque<>(); You can find more details about Deque here. In this problem, you are given N integers. You need to find the maximum number of unique integers among all the possible contiguous subarrays of size M. Note: Time limit is 3 second for this problem. Input Format The first line of input contains two integers N and M: representing the total number of integers and the size of the subarray, respectively. The next line contains N space separated integers. Constraints 1<=N<=100000 1<=M<=100000 M<=N The numbers in the array will range between [0,10000000]. Output Format Print the maximum number of unique integers among all possible contiguous subarrays of size M.

### Solution :

` ````
Solution in C :
import java.util.*;
public class Solution {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
Deque<Integer> deque = new ArrayDeque<Integer>();
HashMap<Integer, Integer> hashmap = new HashMap<Integer, Integer>();
int n = in.nextInt();
int m = in.nextInt();
int ans = 0, distinct = 0;
for (int i = 0; i < n; i++) {
int num = in.nextInt();
deque.addLast(num);
if (hashmap.get(num) == null) hashmap.put(num,0);
hashmap.put(num, hashmap.get(num)+1);
if (hashmap.get(num)==1) distinct++;
if (deque.size() == m+1){
int ele = deque.removeFirst();
hashmap.put(ele, hashmap.get(ele)-1);
if (hashmap.get(ele) == 0) distinct--;
}
if (deque.size() == m){
if (distinct > ans) ans = distinct;
}
}
System.out.println(ans);
in.close();
}
}
```

## View More Similar Problems

## Is This a Binary Search Tree?

For the purposes of this challenge, we define a binary tree to be a binary search tree with the following ordering requirements: The data value of every node in a node's left subtree is less than the data value of that node. The data value of every node in a node's right subtree is greater than the data value of that node. Given the root node of a binary tree, can you determine if it's also a

View Solution →## Square-Ten Tree

The square-ten tree decomposition of an array is defined as follows: The lowest () level of the square-ten tree consists of single array elements in their natural order. The level (starting from ) of the square-ten tree consists of subsequent array subsegments of length in their natural order. Thus, the level contains subsegments of length , the level contains subsegments of length , the

View Solution →## Balanced Forest

Greg has a tree of nodes containing integer data. He wants to insert a node with some non-zero integer value somewhere into the tree. His goal is to be able to cut two edges and have the values of each of the three new trees sum to the same amount. This is called a balanced forest. Being frugal, the data value he inserts should be minimal. Determine the minimal amount that a new node can have to a

View Solution →## Jenny's Subtrees

Jenny loves experimenting with trees. Her favorite tree has n nodes connected by n - 1 edges, and each edge is ` unit in length. She wants to cut a subtree (i.e., a connected part of the original tree) of radius r from this tree by performing the following two steps: 1. Choose a node, x , from the tree. 2. Cut a subtree consisting of all nodes which are not further than r units from node x .

View Solution →## Tree Coordinates

We consider metric space to be a pair, , where is a set and such that the following conditions hold: where is the distance between points and . Let's define the product of two metric spaces, , to be such that: , where , . So, it follows logically that is also a metric space. We then define squared metric space, , to be the product of a metric space multiplied with itself: . For

View Solution →## Array Pairs

Consider an array of n integers, A = [ a1, a2, . . . . an] . Find and print the total number of (i , j) pairs such that ai * aj <= max(ai, ai+1, . . . aj) where i < j. Input Format The first line contains an integer, n , denoting the number of elements in the array. The second line consists of n space-separated integers describing the respective values of a1, a2 , . . . an .

View Solution →