7. Reverse Integer
9. Palindrome Number
13. Roman to Integer
38. Count and Say
66. Plus One
168. Excel Sheet Column Title
169. Majority Element
202. Happy Number
204. Count Primes
231. Power of Two
258. Add Digits
263. Ugly Number
268. Missing Number
292. Nim Game
326. Power of Three
342. Power of Four
405. Convert a Number to Hexadecimal
412. Fizz Buzz
561. Array Partition I
657. Robot Return to Origin
724. Find Pivot Index
728. Self Dividing Numbers
747. Largest Number At Least Twice of Others
888. Fair Candy Swap
942. DI String Match
976. Largest Perimeter Triangle
1281. Subtract the Product and Sum of Digits of an Integer
1295. Find Numbers with Even Number of Digits
6. ZigZag Conversion
12. Integer to Roman
29. Divide Two Integers
31. Next Permutation
43. Multiply Strings
50. Pow(x, n)
60. Permutation Sequence
89. Gray Code
172. Factorial Trailing Zeroes
189. Rotate Array
223. Rectangle Area
264. Ugly Number II
319. Bulb Switcher
357. Count Numbers with Unique Digits