Add solution #14

Author: JoshCrozier

README.md

@@ -11,6 +11,7 @@
 3|[Longest Substring Without Repeating Characters](./0003-longest-substring-without-repeating-characters.js)|Medium|
 4|[Median of Two Sorted Arrays](./0004-median-of-two-sorted-arrays.js)|Hard|
 7|[Reverse Integer](./0007-reverse-integer.js)|Easy|
+14|[Longest Common Prefix](./0014-longest-common-prefix.js)|Easy|
 27|[Remove Element](./0027-remove-element.js)|Easy|
 31|[Next Permutation](./0031-next-permutation.js)|Medium|
 36|[Valid Sudoku](./0036-valid-sudoku.js)|Medium|

solutions/0014-longest-common-prefix.js

@@ -0,0 +1,27 @@
+/**
+ * 14. Longest Common Prefix
+ * https://leetcode.com/problems/longest-common-prefix/
+ * Difficulty: Easy
+ *
+ * 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 `""`.
+ */
+
+/**
+ * @param {string[]} strs
+ * @return {string}
+ */
+var longestCommonPrefix = function(strs) {
+  const prefixes = strs[0].split('').map((_, i) => strs[0].slice(0, i + 1));
+
+  for (let i = strs.length - 1; i > -1; i--) {
+    for (let j = prefixes.length - 1; j > -1; j--) {
+      if (strs[i].substr(0, j + 1) !== prefixes[j]) {
+        prefixes.pop();
+      }
+    }
+  }
+
+  return prefixes.pop() || '';
+};