How to fix the Release Version 5 Not Supported error in IntelliJ
What do you do when you create a new Maven Java project, and when you run it, you get the following error:
Error:java: error: release version 5 not …
Technical Articles
In-depth guides, insights, and best practices for modern software engineering
Facebook’s custom IPv6 range
I noticed an interesting thing with a certain visitor after posting a blog post to Facebook.
The IP address that the Facebook crawler uses to visit …
Read Article →How to Reverse an Integer in Java
The challenge
Given a 32-bit signed integer, reverse digits of an integer.
Example 1:
Example 2:
Example 3:
Note:
Assume we are dealing with an …
Reverse a String in-place using Java
The challenge
Write a function that reverses a string. The input string is given as an array of characters char[].
Do not allocate extra space for …
Read Article →Check if a Java array Contains Duplicates
The challenge
Given an array of integers, find if the array contains any duplicates.
Your function should return true if any value appears at least …
Read Article →Find All Numbers Disappeared in an Array using Python
The challenge
Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.
Find all the …
Read Article →The Array Height Checker Problem in Java
The challenge
Students are asked to stand in non-decreasing order of heights for an annual photo.
Return the minimum number of students that must move …
Read Article →Find the Squares of a Sorted Array in Java
The challenge
Given an array of integers A sorted in non-decreasing order, return an array of the squares of each number, also in sorted …
Sorting a Java Array by Parity
The challenge
Given an array A of non-negative integers, return an array consisting of all the even elements of A, followed by all the odd elements of …
Remove Duplicates from Sorted Array in Java
Say you have an array of primitive integers and you want to remove all duplicates.
You can find out how many non-duplicate integers are in the array …
Read Article →Replace Elements with Greatest Element on Right Side using Java
The challenge
Given an array arr, replace every element in that array with the greatest element among the elements to its right, and replace the last …
The Valid Mountain Array Problem using Java
Introducing the problem
Given an array A of integers, return true if and only if it is a valid mountain array.
Recall that A is a mountain array if …
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