String problems

186 String DSA practice problems on CampusCode, each with statement, examples and constraints.

• 150. Reverse a String Easy String
• 151. Check if String is Palindrome Easy String
• 152. Count Vowels and Consonants Easy String
• 153. Remove All Spaces from a String Easy String
• 154. Count Occurrences of a Character Easy String
• 155. Check if Two Strings are Anagrams Easy String
• 156. Find the First Non-Repeating Character Easy String
• 157. Check if String Contains Only Digits Easy String
• 158. Remove Duplicate Characters from String Easy String
• 159. Reverse Words in a Sentence Easy String
• 160. Find the Length of Last Word Easy String
• 161. Check if String is a Subsequence of Another Easy String
• 162. Roman to Integer Easy String
• 163. Longest Common Prefix Easy String
• 164. Add Binary Strings Easy String
• 165. Valid Parentheses (String Version) Easy String
• 166. Detect Capital Usage Easy String
• 167. To Lower Case Easy String
• 168. Count and Say Easy String
• 169. Merge Strings Alternately Easy String
• 170. Check if Strings are Isomorphic Easy String
• 171. Word Pattern Easy String
• 172. Find the Difference (One Extra Character) Easy String
• 173. Ransom Note Easy String
• 174. String Compression (Run-Length Encoding) Easy String
• 175. Repeated Substring Pattern Easy String
• 176. Check if String is a Rotation of Another Easy String
• 177. Maximum Nesting Depth of Parentheses Easy String
• 178. Find the Index of the First Occurrence in a String Easy String
• 179. Longest Continuous Repeating Character Easy String
• 180. Number of Segments in a String Easy String
• 181. Find All Occurrences of a Substring Easy String
• 182. Maximum Number of Words in Sentences Easy String
• 183. Truncate Sentence Easy String
• 184. Check if Pangram Easy String
• 185. Sorting the Sentence Easy String
• 186. Goal Parser Interpretation Easy String
• 187. Reverse Prefix of Word Easy String
• 188. Remove Vowels from String Easy String
• 189. Largest Odd Number in String Easy String
• 190. Longest Substring Without Repeating Characters (Brute) Easy String
• 191. Count Prefix and Suffix Pairs Easy String
• 192. Check if Binary String Has at Most One Segment of Ones Easy String
• 193. Remove Trailing Zeros from String Easy String
• 194. Count Substrings Starting and Ending with Given Character Easy String
• 195. String Without AAA or BBB Easy String
• 196. Concatenation of Consecutive Binary Numbers (String) Easy String
• 197. Check Distances Between Same Letters Easy String
• 198. Replace All Digits with Characters Easy String
• 199. Check if Two String Arrays are Equivalent Easy String
• 200. Make the String Great (Remove Same Adjacent) Easy String
• 201. Shuffle String Easy String
• 202. Integer to Roman Easy String
• 203. Decode the Message Easy String
• 204. Capitalize the First Letter of Every Word Easy String
• 205. Shift the Letters Easy String
• 206. Minimum Number of Moves to Seat Everyone Easy String
• 207. Largest Number (Array to String Sort) Easy String
• 208. Decode String (Nested Brackets — Easy Variant) Easy String
• 209. Longest Substring with At Most Two Distinct Characters Easy String
• 210. Longest Substring Without Repeating Characters Medium String
• 211. Longest Palindromic Substring Medium String
• 212. Group Anagrams Medium String
• 213. Longest Palindrome by Rearranging Characters Medium String
• 214. Minimum Window Substring Medium String
• 215. String to Integer (atoi) Medium String
• 216. ZigZag Conversion Medium String
• 217. Multiply Strings Medium String
• 218. Decode Ways Medium String
• 219. Word Break Medium String
• 220. Generate Parentheses (Count) Medium String
• 221. Letter Combinations of a Phone Number (Count) Medium String
• 222. Restore IP Addresses (Count) Medium String
• 223. Count Palindromic Substrings Medium String
• 224. Longest Repeating Character Replacement Medium String
• 225. Valid Palindrome II Medium String
• 226. Palindrome Partitioning (Count) Medium String
• 227. Reorganize String (Feasibility) Medium String
• 228. Find All Anagrams in a String (Count) Medium String
• 229. Permutation in String Medium String
• 230. Compare Version Numbers Medium String
• 231. Reverse Words in a String Medium String
• 232. Simplify Path Medium String
• 233. Basic Calculator II Medium String
• 234. Decode String Medium String
• 235. Custom Sort String Medium String
• 236. Partition Labels (Count) Medium String
• 237. Count Distinct Subsequences (Modulo 10^9+7) Medium String
• 238. String Compression (Length) Medium String
• 239. Remove K Digits Medium String
• 240. Remove Duplicate Letters Medium String
• 241. Text Justification (Line Count) Medium String
• 242. Sort Characters By Frequency Medium String
• 243. Find the Index of the First Occurrence Medium String
• 244. Repeated DNA Sequences (Count) Medium String
• 245. Isomorphic Strings Medium String
• 246. Reverse Vowels of a String Medium String
• 247. Largest Number Medium String
• 248. Number of Distinct Substrings (Count) Medium String
• 249. Minimum Add to Make Parentheses Valid Medium String
• 250. Longest Substring with At Most K Distinct Characters Medium String
• 251. Substring with Concatenation of All Words (Count) Medium String
• 252. Find Longest Word by Deleting Characters Medium String
• 253. CamelCase Matching (Count) Medium String
• 254. Maximum Number of Vowels in a Substring of Given Length Medium String
• 255. Defanging an IP Address Medium String
• 256. Bulls and Cows Medium String
• 257. Edit Distance Hard String
• 258. Wildcard Matching Hard String
• 259. Regular Expression Matching Hard String
• 260. Longest Valid Parentheses Hard String
• 261. Distinct Subsequences (Count Target in Source) Hard String
• 262. Word Break II (Count of Segmentations) Hard String
• 263. Shortest Palindrome (Prepend Count) Hard String
• 264. Palindrome Pairs (Count) Hard String
• 265. Minimum Window Subsequence (Length) Hard String
• 266. Scramble String Hard String
• 267. Interleaving String Hard String
• 268. Longest Duplicate Substring (Length) Hard String
• 269. Word Ladder (Shortest Transformation Length) Hard String
• 270. Concatenated Words (Count) Hard String
• 271. Valid Number Hard String
• 272. Count Different Palindromic Subsequences (Modulo 10^9+7) Hard String
• 273. Palindrome Partitioning II (Minimum Cuts) Hard String
• 274. Distinct Echo Substrings (Count) Hard String
• 275. Last Substring in Lexicographical Order Hard String
• 276. Minimum Insertions to Make a Palindrome Hard String
• 277. Minimum Insertions to Balance Parentheses Hard String
• 278. Longest Substring with At Least K Repeating Characters Hard String
• 279. Basic Calculator Hard String
• 280. Different Ways to Add Parentheses (Count) Hard String
• 281. Expression Add Operators (Count) Hard String
• 282. Ambiguous Coordinates (Count) Hard String
• 283. Number of Ways to Form Target String (Modulo 10^9+7) Hard String
• 284. Stamping The Sequence (Stamp Count) Hard String
• 285. Integer to English Words Hard String
• 286. Parse Lisp Expression Hard String
• 287. Number of Atoms Hard String
• 288. Encode String with Shortest Length Hard String
• 289. Distinct Subsequences II (Modulo 10^9+7) Hard String
• 290. Partition into Substrings with Unique Characters Hard String
• 291. Shortest Superstring (Length) Hard String
• 292. Count Substrings That Differ by One Character Hard String
• 293. Longest Happy Prefix (Length) Hard String
• 294. Strong Password Checker (Minimum Steps) Hard String
• 295. Count Generalized Abbreviations (Modulo 10^9+7) Hard String
• 296. Special Binary String Hard String
• 412. Find All Anagrams via Sliding Window Hard Linked List
• 557. Longest Substring with At Most K Replacements Hard Binary Search
• 564. Check Balanced Parentheses Easy Stack
• 565. Reverse a String Using Stack Easy Stack
• 567. Convert Infix to Postfix Easy Stack
• 572. Check if Stack is Palindrome Easy Stack
• 575. Valid Parentheses (Multiple Types) Easy Stack
• 576. Remove All Adjacent Duplicates in String Easy Stack
• 577. Make String Great Easy Stack
• 587. First Non-Repeating Character in Stream Easy Stack
• 597. Balanced Brackets with Wildcard Easy Stack
• 598. Maximum Nesting Depth of Parentheses Easy Stack
• 601. Delete Consecutive Same Words Easy Stack
• 602. Count Pairs of Matching Parentheses Easy Stack
• 603. Simplify Unix Directory Path Easy Stack
• 604. Score of Parentheses Easy Stack
• 605. Remove K Digits to Get Smallest Number Easy Stack
• 612. Decode String (Nested Brackets) Medium Stack
• 615. Remove Duplicate Letters Medium Stack
• 634. Count Collisions on a Road Medium Stack
• 635. Minimum Add to Make Parentheses Valid Medium Stack
• 636. Minimum Insertions to Balance Parentheses Medium Stack
• 637. Longest Valid Parentheses Medium Stack
• 638. Number of Atoms Medium Stack
• 648. Removing Stars From a String Medium Stack
• 651. Check If Word Is Valid After Substitutions Medium Stack
• 652. Implement a Basic Calculator II Medium Stack
• 656. Basic Calculator I Hard Stack
• 657. Basic Calculator III Hard Stack
• 658. Longest Valid Parentheses (O(1) Space) Hard Stack
• 659. Remove Invalid Parentheses Hard Stack
• 665. Minimum Swaps to Make String Balanced Hard Stack
• 930. Replace Words Using Trie (Sentence Shortening) Medium Trees
• 948. Palindrome Pairs (Trie Approach) Hard Trees
• 949. Stream of Characters (Aho-Corasick Lite) Hard Trees
• 1288. Invert Case of All Characters in a String Easy Bit Manipulation
• 1321. Find the Difference Between Two Strings (XOR) Easy Bit Manipulation
• 1329. Power Set Using Bitmask Medium Bit Manipulation
• 1345. Stickers to Spell Word — Bitmask DP Medium Bit Manipulation