Coding Problems

Free Problems (74)

Title	Category	Difficulty
Backspace String Compare	Two Pointers	Easy
Balanced Binary Tree	Tree	Easy
Best Time to Buy and Sell Stock	Dynamic Programming	Easy
Best Time to Buy and Sell Stock	Array	Easy
Binary Search	Binary Search	Easy
Climbing Stairs	Dynamic Programming	Easy
Combine Two Tables	SQL	Easy
Concatenation of Array	Arrays	Easy
Contains Duplicate	Array	Easy
Contains Duplicate II	Hash Table	Easy
Counting Bits	Array	Easy
Diameter of Binary Tree	Tree	Easy
First Unique Character in a String	Hash Table	Easy
Happy Number	Hash Table	Easy
Happy Number Math	Math	Easy
Implement strStr()	String	Easy
Invert Binary Tree	Tree	Easy
Isomorphic Strings	Hash Table	Easy
Is Subsequence	String	Easy
Linked List Cycle	Two Pointers	Easy
Longest Common Prefix	String	Easy
Lucky Numbers in a Matrix	Matrix	Easy
Majority Element	Arrays	Easy
Maximum Depth of Binary Tree	Tree	Easy
Meeting Rooms	Intervals	Easy
Merge Sorted Array	Two Pointers	Easy
Merge Two Sorted Lists	Linked List	Easy
Missing Number	Array	Easy
Move Zeroes	Array	Easy
Next Greater Element I	Stack	Easy
Number of 1 Bits	Array	Easy
Palindrome Linked List	Linked List	Easy
Palindrome Number	Math	Easy
Path Sum	Tree	Easy
Plus One	Array	Easy
Ransom Note	Hash Table	Easy
Remove Duplicates from Sorted Array	Two Pointers	Easy
Remove Duplicates from Sorted List	Linked List	Easy
Remove Element	Two Pointers	Easy
Reverse Bits	Array	Easy
Reverse Linked List	Linked List	Easy
Roman to Integer	String	Easy
Same Tree	Tree	Easy
Search Insert Position	Binary Search	Easy
Single Number	Bit Manipulation	Easy
Sqrt(x)	Binary Search	Easy
Sqrt(x) Math	Math	Easy
Squares of a Sorted Array	Two Pointers	Easy
Subtree of Another Tree	Tree	Easy
Toeplitz Matrix	Matrix	Easy
Two Sum	Array	Easy
Valid Anagram	String	Easy
Valid Palindrome	String	Easy
Valid Palindrome II	Two Pointers	Easy
Valid Parentheses	String	Easy
Word Pattern	Hash Table	Easy
3Sum	Array	Medium
Best Time to Buy and Sell Stock II	Sliding Window	Medium
Container With Most Water	Array	Medium
Find Minimum in Rotated Sorted Array	Array	Medium
Find the Duplicate Number	Array	Medium
Group Anagrams	String	Medium
Longest Substring Without Repeating Characters	String	Medium
Maximum Product Subarray	Array	Medium
Maximum Subarray	Array	Medium
Merge Two Sorted Linked Lists	Linked Lists	Medium
Next Permutation	Arrays	Medium
Product of Array Except Self	Array	Medium
Reverse Words in a String	String	Medium
Rotate Array	Array	Medium
Search in Rotated Sorted Array	Array	Medium
Shortest Path in Binary Matrix	Graphs	Medium
Sort Colors	Two Pointers	Medium
Two Sum II - Input Array Is Sorted	Hash Table	Medium

Coding Problems

Free Problems (74)

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