Math
60 problems — 31 easy, 26 medium, 3 hard.
| # | Title | Difficulty | Frequency |
|---|---|---|---|
| 7 | Reverse Integer | medium | frequently asked |
| 8 | String to Integer (atoi) | medium | frequently asked |
| 9 | Palindrome Number | easy | foundational |
| 12 | Integer to Roman | medium | frequently asked |
| 13 | Roman to Integer | easy | foundational |
| 29 | Divide Two Integers | medium | frequently asked |
| 38 | Count and Say | medium | frequently asked |
| 43 | Multiply Strings | medium | frequently asked |
| 50 | Pow(x, n) | medium | frequently asked |
| 66 | Plus One | easy | foundational |
| 67 | Add Binary | easy | foundational |
| 69 | Sqrt(x) | easy | foundational |
| 136 | Single Number | easy | frequently asked |
| 166 | Fraction to Recurring Decimal | medium | less common |
| 168 | Excel Sheet Column Title | easy | foundational |
| 169 | Majority Element | easy | frequently asked |
| 171 | Excel Sheet Column Number | easy | foundational |
| 172 | Factorial Trailing Zeroes | medium | frequently asked |
| 190 | Reverse Bits | easy | foundational |
| 191 | Number of 1 Bits | easy | foundational |
| 202 | Happy Number | easy | frequently asked |
| 204 | Count Primes | medium | frequently asked |
| 224 | Basic Calculator | hard | frequently asked |
| 227 | Basic Calculator II | medium | frequently asked |
| 231 | Power of Two | easy | foundational |
| 246 | Strobogrammatic Number | easy | less common |
| 258 | Add Digits | easy | foundational |
| 263 | Ugly Number | easy | foundational |
| 264 | Ugly Number II | medium | frequently asked |
| 268 | Missing Number | easy | frequently asked |
| 279 | Perfect Squares | medium | frequently asked |
| 287 | Find the Duplicate Number | medium | frequently asked |
| 313 | Super Ugly Number | medium | less common |
| 319 | Bulb Switcher | medium | less common |
| 326 | Power of Three | easy | foundational |
| 338 | Counting Bits | easy | frequently asked |
| 342 | Power of Four | easy | foundational |
| 343 | Integer Break | medium | frequently asked |
| 365 | Water and Jug Problem | medium | less common |
| 367 | Valid Perfect Square | easy | foundational |
| 399 | Evaluate Division | medium | frequently asked |
| 400 | Nth Digit | medium | less common |
| 412 | Fizz Buzz | easy | foundational |
| 415 | Add Strings | easy | foundational |
| 441 | Arranging Coins | easy | foundational |
| 507 | Perfect Number | easy | foundational |
| 728 | Self Dividing Numbers | easy | foundational |
| 754 | Reach a Number | medium | less common |
| 812 | Largest Perimeter Triangle | easy | foundational |
| 858 | Mirror Reflection | medium | less common |
| 878 | Nth Magical Number | hard | less common |
| 914 | X of a Kind in a Deck of Cards | easy | less common |
| 970 | Powerful Integers | medium | less common |
| 991 | Broken Calculator | medium | frequently asked |
| 1015 | Smallest Integer Divisible by K | medium | less common |
| 1071 | Greatest Common Divisor of Strings | easy | frequently asked |
| 1175 | Prime Arrangements | easy | less common |
| 1232 | Check If It Is a Straight Line | easy | foundational |
| 1250 | Check If It Is a Good Array | hard | less common |
| 1344 | Angle Between Hands of a Clock | medium | less common |