14. Longest Common Prefix

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 "".

Example 1:

Input: ["flower","flow","flight"]

Output: "fl"

Example 2:

Input: ["dog","racecar","car"]

Output: ""

Explanation: There is no common prefix among the input strings.

Note:

All given inputs are in lowercase letters a-z.

My implementation:

Description originally from leetcode.com