14-easy-Longest_Common_Prefix.js

/**
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.
 */

/**
 * @param {string[]} strs
 * @return {string}
 */
var longestCommonPrefix = function (strs) {
  var prefix = strs[0] || ''
  for (var i = 1, j = strs.length; i < j; i++) {
    while (strs[i].indexOf(prefix) !== 0) {
      prefix = prefix.slice(0, -1)
    }
  }

  return prefix
}