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Java: Find the maximum number inside the number in the window

Java Basic: Exercise-174 with Solution

Write a Java program to find the maximum number inside the number in the window (size k) at each step in a given array of integers with duplicate numbers. Move the window to the top of the array.

{|1, 2, 3|, 4, 5, 6, 7, 8, 8} -> Return maximum 3
{1, |2, 3, 4|, 5, 6, 7, 8, 8} -> Return maximum 4
{1, 2, |3, 4, 5|, 6, 7, 8, 8} -> Return maximum 5
{1, 2, 3, |4, 5, 6|, 7, 8, 8} -> Return maximum 6
{1, 2, 3, 4, |5, 6, 7|, 8, 8} -> Return maximum 7
{1, 2, 3, 4, 5, |6, 7, 8|, 8} -> Return maximum 8
{1, 2, 3, 4, 5, 6, |7, 8, 8|} -> Return maximum 8
Result array {3, 4, 5, 6, 7, 8, 8}

Sample Solution:

Java Code:

import java.util.*;
import java.util.Arrays;
import java.util.LinkedList;

public class Solution {
   public static void main(String[] args) {
       	int[] main_array = {1, 2, 3, 4, 5, 6, 7, 8, 8};
		int k = 3;
		System.out.println("\nOriginal array: "+Arrays.toString(main_array));  
		System.out.println("\nValue of k: "+k);  
        System.out.println("\nResult: ");   
        ArrayList result = max_slide_window(main_array,k);
        for (int i = 0; i < result.size(); i++) {
            System.out.println(result.get(i));
        }
    }
  public static ArrayList max_slide_window(int[] main_array, int k) {
    	ArrayList rst_arra = new ArrayList();
    	if (main_array == null || main_array.length == 0 || k < 0) {
    		return rst_arra;
    	}
    	Deque deque_num = new LinkedList();
    	for (int i = 0; i < k; i++) {
    		while (!deque_num.isEmpty() && main_array[deque_num.peekLast()] <= main_array[i]) {
    			deque_num.pollLast();
    		}
    		deque_num.offerLast(i);
    	}

    	for (int i = k; i < main_array.length; i++) {
    		rst_arra.add(main_array[deque_num.peekFirst()]);
    		if (!deque_num.isEmpty() && deque_num.peekFirst() <= i - k) {
    			deque_num.pollFirst();
    		}
    		while (!deque_num.isEmpty() && main_array[deque_num.peekLast()] <= main_array[i]) {
    			deque_num.pollLast();
    		}
    		deque_num.offerLast(i);
    	}
    	rst_arra.add(main_array[deque_num.peekFirst()]);
    	return rst_arra;
    }
}

Sample Output:

Original array: [1, 2, 3, 4, 5, 6, 7, 8, 8]

Value of k: 3

Result: 
3
4
5
6
7
8
8

Pictorial Presentation:

Java exercises: Find the maximum number inside the number in the window

Flowchart:

Flowchart: Java exercises: Find the maximum number inside the number in the window.

Java Code Editor:

Company:  Zenefits Google Amazon

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Previous: Write a Java program to find the median of the number inside the window (size k) at each moving in a given array of intergers with duplicate numbers. Move the window from the start of the array.
Next: Write a Java program to delete a specified node in the middle of a singly linked list.

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Java: Tips of the Day

DropElements

Removes elements in an array until the passed function returns true. Returns the remaining elements in the array.

Loop through the array, using Arrays.copyOfRange() to drop the first element of the array until the returned value from the function is true. Returns the remaining elements.

public static int[] dropElements(int[] elements, IntPredicate condition) {
    while (elements.length > 0 && !condition.test(elements[0])) {
        elements = Arrays.copyOfRange(elements, 1, elements.length);
    }
    return elements;
}

Ref: https://bit.ly/37YWqzD

 





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