8. String to Integer (atoi) https://leetcode.com/problems/string-to-integer-atoi
9. Palindrome Number https://leetcode.com/problems/palindrome-number
50. Pow(x, n) https://leetcode.com/problems/powx-n
67. Add Binary https://leetcode.com/problems/add-binary
400. Nth Digit https://leetcode.com/problems/nth-digit
306. Additive Number https://leetcode.com/problems/additive-number
842. Split Array into Fibonacci Sequence https://leetcode.com/problems/split-array-into-fibonacci-sequence
357. Count Numbers with Unique Digits https://leetcode.com/problems/count-numbers-with-unique-digits
279. Perfect Squares https://leetcode.com/problems/perfect-squares
