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String

String

Overall Progress0/106(0%)

Easy

0/27

Medium

0/52

Hard

0/27

Longest Substring Without Repeating Characters

Medium

Longest Palindromic Substring

Medium

Valid Parentheses

Easy

Generate Parentheses

Medium

Medium

Letter Combinations of a Phone Number

Medium

Longest Common Prefix

Easy

Minimum Window Substring

Hard

Medium

Medium

Roman to Integer

Easy

Longest Valid Parentheses

Hard

Easy

Find All Anagrams in a String

Medium

Regular Expression Matching

Hard

Hard

Medium

Permutation in String

Medium

Implement Trie (Prefix Tree)

Medium

Palindromic Substrings

Medium

Serialize and Deserialize Binary Tree

Hard

Valid Palindrome

Easy

Easy

Hard

Evaluate Division

Medium

First Unique Character in a String

Easy

Reorganize String

Medium

Sort Characters By Frequency

Medium

Wildcard Matching

Hard

Valid Palindrome II

Easy

Top K Frequent Words

Medium

Design Add and Search Words Data Structure

Medium

Backspace String Compare

Easy

Hard

Multiply Strings

Medium

Minimum Remove to Make Valid Parentheses

Medium

Medium

Binary Tree Paths

Easy

Remove All Adjacent Duplicates In String

Easy

Basic Calculator

Hard

Longest Substring with At Least K Repeating Characters

Medium

Valid Parenthesis String

Medium

Basic Calculator II

Medium

Hard

Remove Invalid Parentheses

Hard

Remove All Adjacent Duplicates in String II

Medium

Medium

Excel Sheet Column Title

Easy

String Compression

Medium

Easy

String to Integer (atoi)

Medium

Verifying an Alien Dictionary

Easy

Medium

Reverse Vowels of a String

Easy

Minimum Add to Make Parentheses Valid

Medium

Palindrome Pairs

Hard

Alien Dictionary

Hard

Medium

Custom Sort String

Medium

Integer to English Words

Hard

Serialize and Deserialize BST

Medium

Expression Add Operators

Hard

Easy

Check If Two String Arrays are Equivalent

Easy

Longest Substring with At Most K Distinct Characters

Medium

Easy

Repeated String Match

Medium

Maximum Nesting Depth of the Parentheses

Easy

Similar String Groups

Hard

Prefix and Suffix Search

Hard

Longest Substring with At Most Two Distinct Characters

Medium

Fraction to Recurring Decimal

Medium

Longest Word in Dictionary

Medium

Count Different Palindromic Subsequences

Hard

Count Items Matching a Rule

Easy

Stream of Characters

Hard

Uncommon Words from Two Sentences

Easy

Group Shifted Strings

Medium

Hard

Stamping The Sequence

Hard

Minimum Window Subsequence

Hard

One Edit Distance

Medium

Hard

Remove Sub-Folders from the Filesystem

Medium

Longest Absolute File Path

Medium

Shortest Way to Form String

Medium

Stickers to Spell Word

Hard

Minimum Insertions to Balance a Parentheses String

Medium

Basic Calculator III

Hard

Maximum Number of Occurrences of a Substring

Medium

Check if One String Swap Can Make Strings Equal

Easy

Add Bold Tag in String

Medium

Construct Binary Tree from String

Medium

Palindrome Permutation

Easy

Validate IP Address

Medium

Rearrange String k Distance Apart

Hard

Easy

Strobogrammatic Number II

Medium

Valid Word Abbreviation

Easy

Valid Palindrome III

Hard

Strobogrammatic Number

Easy

Groups of Special-Equivalent Strings

Medium

Maximum Nesting Depth of Two Valid Parentheses Strings

Medium

Vowel Spellchecker

Medium

Unique Word Abbreviation

Medium

Sentence Similarity

Easy