Test if you are ready for a software development job by solving all of the challenges below. Challenges are sorted by difficulty. If you need help with the challenges, request a free hour of online private tutoring.

Array
String
Dictionary
Dynamic Programming
Recursion
Tree

Reverse String
Kids with the Greatest Number of Candies
Max Consecutive Ones
Third Maximum Number
Largest Number At Least Twice of Others
Check If It Is a Straight Line
Plus One
Find Pivot Index
How Many Numbers Are Smaller Than the Current Number
Replace Elements with Greatest Element on Right Side
Best Time to Buy and Sell Stock
Squares of a Sorted Array
Element Appearing More Than 25% in Sorted Array
Move Zeroes
Remove Duplicates from Sorted Array
Can Place Flowers
Create Target Array in the Given Order
Duplicate Zeros
Monotonic Array
Valid Mountain Array
Best Time to Buy and Sell Stock II
Maximum Subarray
Image Smoother
Shift 2D Grid

Valid Palindrome
Student Attendance Record I
Reverse Vowels of a String
Reverse Only Letters
Detect Capital
Is Subsequence
Valid Parentheses
Backspace String Compare
Goat Latin
Implement strStr()
Positions of Large Groups
Longest Common Prefix
Long Pressed Name
Valid Palindrome II
Longest Palindromic Substring
Camelcase Matching

Contains Duplicate
Single Number
First Unique Character in a String
N-Repeated Element in Size 2N Array
Majority Element
Jewels and Stones
Check If N and Its Double Exist
Find All Numbers Disappeared in an Array
Find Lucky Integer in an Array
Unique Number of Occurrences
Intersection of Two Arrays
Intersection of Two Arrays II
Minimum Index Sum of Two Lists
Find the Difference
Uncommon Words from Two Sentences
Buddy Strings
Isomorphic Strings
Two Sum
Pairs of Songs with Total Durations Divisible by 60
Fair Candy Swap
Set Mismatch
Keyboard Row
Ransom Note
Maximum Number of Balloons
Find the Town Judge
Valid Anagram
Roman to Integer
Find Words That Can Be Formed by Characters
Find Common Characters
Shortest Completing Word
Longest Substring Without Repeating Characters
Group Anagrams
Top K Frequent Elements
Valid Sudoku
Alphabet Board Path
Task Scheduler

Fibonacci Number
N-th Tribonacci Number
Pascal's Triangle
Pascal's Triangle II
Climbing Stairs
Min Cost Climbing Stairs
House Robber
Divisor Game
Unique Paths
Minimum Path Sum
Longest Increasing Subsequence
2 Keys Keyboard

Number of Steps to Reduce a Number to Zero
Power of Three
Add Digits
Happy Number
Last Stone Weight
Count and Say
Pow(x, n)
K-th Symbol in Grammar
Jump Game
Keys and Rooms
Number of Islands
Friend Circles
Word Search
Time Needed to Inform All Employees
Subsets
Combinations
Coin Change
Target Sum
Letter Combinations of a Phone Number
Permutations
Perfect Squares
Maximal Square
Open the Lock
Generate Parentheses

Binary Tree Preorder Traversal
Binary Tree Inorder Traversal
Binary Tree Postorder Traversal
Binary Tree Level Order Traversal
Same Tree
Univalued Binary Tree
Maximum Depth of Binary Tree
Path Sum
Sum of Left Leaves
Binary Tree Paths
Merge Two Binary Trees
Symmetric Tree