Solve exercise 1.2 by sorting the strings.

Author: Isaac Ramirez

src/chapters/01/exercises/check-permutation/index.js

@@ -1,7 +1,7 @@
 /*  Book solutions */
 const {} = require("./book-solutions");
 /* My solutions */
-const { v1 } = require("./my-solutions");
+const { v1, v2 } = require("./my-solutions");
 
 /* Export the solution to be tested */
-module.exports = v1;
+module.exports = v2;

src/chapters/01/exercises/check-permutation/my-solutions/check-permutation.v2.js

@@ -0,0 +1,22 @@
+/**
+ * Sorting both strings and compare.
+ * Running time: Depends on the sorting algorithm.
+ * @param {string} str1
+ * @param {string} str2
+ * @returns {boolean}
+ */
+function checkPermutation(str1, str2) {
+  // if lengths are different, then permutation is not possible.
+  if (str1.length !== str2.length) return false;
+
+  const sort1 = str1.split("").sort();
+  const sort2 = str2.split("").sort();
+
+  for (let i = 0; i < sort1.length; i++) {
+    if (sort1[i] !== sort2[i]) return false;
+  }
+
+  return true;
+}
+
+module.exports = checkPermutation;

src/chapters/01/exercises/check-permutation/my-solutions/index.js

@@ -1,3 +1,4 @@
 module.exports = {
   v1: require("./check-permutation.v1"),
+  v2: require("./check-permutation.v2"),
 };