Separate even numbers and odd numbers in an array in Java Given an array[], write a function that segregates even and odd numbers. The functions we are going to create should put all even numbers first, and then odd numbers. Here we will learn to separate even and odd numbers in an array in Java. In this Java tutorial, we are going to find a function that segregates even and odd numbers without considering order. We are going to use the quick-sort algorithm in this problem.

Quick-sort is also a Divide and Conquer algorithm like merge-sort. It partitions the given array along a picked pivot element. There are different ways of choosing the pivot element we can choose any element as a pivot element. In Quick-sort algorithm pivoted element is made to put in its correct position. Such that all element before the pivot. Similarly, in this problem, we can take an element as the pivot and put all even numbers before it and all odd numbers after it.

Similarly, using this algorithm we can solve segregating 0 and 1 in an array type problem. These problems are variations of the famous Dutch national flag problem. I hope this tutorial on How to separate even and odd numbers in Java will help you to understand the logic behind achieving our goal.

Your email address will not be published. Separate even and odd numbers in an array in Java By divyesh srivastava. Aadarsh says:. January 9, at pm. Leave a Reply Cancel reply Your email address will not be published. Checking for Duplicacy in an array using Hashing Technique in Java ».

This site uses cookies: more info Okay.Given an array of integers, you need to segregate odd and even numbers in an array. Please note : Order of elements can be changed.

For example:. Java code to separate odd and even numbers in an array : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 package org. In this post, we will see how to sort an array of 0s, 1s and 2s. We have already seen a post on sort 0s and 1s in an array. Problem Given an array containing zeroes, […]. Check if it is possible to have […]. In this post, we will see how to check if array elements are consecutive.

Problem Given an array, we need to check if array contains consecutive elements. In this post, we will see how to find the local minima in the array. Problem An element is local minima if it is less than its neighbors. In this post, we will see about Sliding Window Maximum in java Problem Given an Array of integers and an Integer k, Find the maximum element of from all the contiguous subarrays of size K.

Go to our job portal. Looking for tech […]. In this post, we will see how to count number of occurrences or frequency of each element in a sorted array Problem Given a Sorted Array of integers containing duplicates. Find the frequency of every […]. Very helpful but how can we merge two unsorted arrays and also find smaller number of that unsorted array.

Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. Tech Jobs. Problem : Given an array of integers, you need to segregate odd and even numbers in an array.

Array after separating odd and even numbers :. Original Array :. Array after separating even and odd numbers :. Sort an array of 0s, 1s and 2s. Check if it is possible to reach end of given Array by Jumping. Check if Array Elements are Consecutive. Find the local minima in array. Sliding Window Maximum in java. Count number of occurrences or frequency of each element in a sorted array. Find subarrays with given sum in an array. Find peak element in the array. Find first repeating element in an array of integers.

Prev Find leaders in an array. Next find minimum element in a sorted and rotated array. Arpit Mandliya.Thread Rating: 2 Vote s - 3. Thread Modes. Posts: 3. Reputation: 0. No need to move the number 0 should it occur.

Bass Not Blown Up Yet. Posts: Reputation: 3. My thoughts. Once the odd numbers have been sorted. Scan the original array, search for even numbers, once you have an even number, calculate its position and then insert it into the new array in that position. Is this what you are looking for? Posts: 3, Reputation: Sorting the odd numbers, and then inserting the evens at their original index, would probably be the easiest way, but my guess is that it'd also be the slowest, since you're effectively sorting the list twice.

How important is efficiency? How big are the lists you're sorting? Posts: 4, I was thinking scan the original array, and whenever there is an odd number, replace it with the next number from the sorted array. Thinking through it I think Bass's solution would be easier to implement, especially using enumerate.

Craig "Ichabod" O'Brien - xenomind. Recommended Tutorials: BBCodefunctionsclassestext adventures. Website Find. Jul, PM nilamo Wrote: Sorting the odd numbers, and then inserting the evens at their original index, would probably be the easiest way, but my guess is that it'd also be the slowest, since you're effectively sorting the list twice.

What would be faster? It's not double sorting, it's sorting once and making one pass. Anything quicker would require keeping the evens in place while sorting once. That would require rewriting the sort algorithm, which I expect would be slower than the optimized sort method.

Posts: 7, View a Printable Version.

User Panel Messages. Log Out. View private messages unread.Join Stack Overflow to learn, share knowledge, and build your career. Connect and share knowledge within a single location that is structured and easy to search. I am kind of stuck with this logic. What i need is separate the Even number and odd numbers i. This needs to be done with array only not collection. My approach was:- 1. But i think its not a good approach.

Can anyone help me to this logic correct with algo and code example. Apply any sorting algorithm and use as a comparator a function that considers even numbers "smaller" than odd numbers.

This enables you to use a good sorting algorithm while still sorting the elements the way you want to.

**Sort 3 numbers in descending order without using loop**

Moving around things in arrays is not that efficient since data are stored sequentially. If you don't want to use another structure you could instead sort a first O nlogn. While sorting you can easily count how many even numbers you have, so you know the position of the first odd number.

Then create a second array let's say b and add to it all even numbers from a starting from 0 and odd numbers starting from the position of the first odd number. You can do this in O none parse. What you can do is take two treemap in java. One for even numbers and one for odd numbers.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more.Join Stack Overflow to learn, share knowledge, and build your career. Connect and share knowledge within a single location that is structured and easy to search.

I have an array where i have some numbers. Now i want to sort even numbers in a separate array and odd numbers in a separate.

Is there any API to do that. I tried like this. Note that all the even numbers show up first, then all the odd numbers. Within each group, the numbers are sorted naturally. Your question as stated doesn't make sense, and neither does the code.

So I'm guessing that you want to separate the elements of an array into two arrays, one containing odds and the other evens. If so, do it like this:. If you really want to use arrays but you shouldn't you can do something like this to resize one :. So if you still want to use array for some reasons but you still shouldn't here is a code to filter, resize and sort your array.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 10 years, 5 months ago. Active 3 years, 11 months ago. Viewed 40k times. Improve this question. Colin Hebert Sumithra Sumithra 6, 18 18 gold badges 48 48 silver badges 49 49 bronze badges. Please tag it so What did you try?

There is an overhead on space - Are you talking about a million numbers? Add a comment. Active Oldest Votes. Plain and simple.Given an array arr[] containing N integers, the task is to rearrange the array such that the odd indexed elements are in reverse order. Approach: To solve the problem mentioned above follow the steps given below: Push the elements of odd indexes of the given array into a stack data structure. Replace the current array elements at odd indexes with elements at top of the stack and keep popping until the stack is empty.

Peek ; st. Skip to content. Related Articles. Last Updated : 29 Sep, Python3 program to reverse the. Function to get top of the stack. Pushing elements at odd indexes. Replacing current elements at odd. This code is contributed by akhilsaini. Push x. Peek. Pop. Recommended Articles. Check if the array can be sorted only if the elements on given positions can be swapped. Rearrange array by interchanging positions of even and odd elements in the given array.

Make all the elements of array odd by incrementing odd-indexed elements of odd-length subarrays. Positive elements at even and negative at odd positions Relative order not maintained. Numbers with a Fibonacci difference between Sum of digits at even and odd positions in a given range. Count of unique pairs i, j in an array such that sum of A[i] and reverse of A[j] is equal to sum of reverse of A[i] and A[j].

Minimum flips of odd indexed elements from odd length subarrays to make two given arrays equal. Construct smallest N-digit number possible by placing digits at positions specified by given array. Number of positions such that adding K to the element is greater than sum of all other elements. Article Contributed By :. Easy Normal Medium Hard Expert. Most popular in Arrays. Append digits to the end of dupicate strings to make all strings in an array unique Merge two sorted arrays Program to find largest element in an array Building Heap from Array Find Second largest element in an array.

Most visited in Data Structures. Writing code in comment? Please use ide. Load Comments. We use cookies to ensure you have the best browsing experience on our website.We are given an array of n distinct numbers.

The task is to sort all even-placed numbers in increasing and odd-placed numbers in decreasing order. The modified array should contain all sorted even-placed numbers followed by reverse sorted odd-placed numbers.

Note that the first element is considered as even placed because of its index 0. The idea is simple. We create two auxiliary arrays evenArr[] and oddArr[] respectively. We traverse input array and put all even-placed elements in evenArr[] and odd placed elements in oddArr[].

### Java Program to print Odd and Even Numbers from an Array

Then we sort evenArr[] in ascending and oddArr[] in descending order. Finally copy evenArr[] and oddArr[] to get the required result. Sort ; oddArr. Skip to content. Related Articles. Python3 program to separately sort. Put elements in oddArr[] and evenArr[].

## Separate odd and even numbers in an array

This code is contributed by Mohit Kumar. Add arr[i]. Sort. Reverse. Python3 Program to sort even-placed elements in increasing and.

Sort first half in increasing. Sort second half in decreasing. This code is contributed by Arnab Kundu. Recommended Articles.

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