문제 190. Reverse Bits

주어진 32비트 unsigned integer를 역순으로 만들어 리턴하는 문제이다.
Reverse bits of a given 32 bits unsigned integer.

문제 172. Factorial Trailing Zeroes

주어진 int n을 팩토리얼로 나타내어 Trailing Zeroes를 구하는 문제이다.
Given an integer n, return the number of trailing zeroes in n!.

문제 136. Single Number

주어진 array안에 쌍이 아닌 홀로 있는 숫자를 찾는 문제이다.
Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

문제 125. Valid Palindrome

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
Note: For the purpose of this problem, we define empty string as valid palindrome.

문제 14. Longest Common Prefix

공통으로 가장 긴 접두사를 찾는 문제이다.

Write a function to find the longest common prefix string amongst an array of strings.
If there is no common prefix, return an empty string “”.
strs[i] consists of only lower-case English letters.

문제 13. Roman to Integer

로마숫자를 아라비아숫자로 나타내는 문제이다.
Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M.

For example, 2 is written as II in Roman numeral, just two one’s added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II.