Merge pull request #124 from dawsonbotsford/master

Removed node_modules and completed 1_2 and 1_3

javascript/lib/data-structures/chapter-1/1_2.js

@@ -0,0 +1,27 @@
+module.exports = Strings_1_2 = (function() {
+  return {
+
+   // NOT inline solution (left here to learn from)
+   //  reverseString: function(str) {
+   //    if (str.length === 0) {
+   //      return '';
+   //    }
+   //    return  str[str.length - 1] + arguments.callee(str.substr(0, str.length - 1));
+   // }
+   //
+   //
+
+    /*
+     * Reverses a string inline recursively
+     * @param {String} str - The string to be reversed
+     * @returns {String} The reversed string
+     */
+    reverseString: function(str) {
+      var len = str.length;
+      if (len > 1) {
+        return str[len - 1] + arguments.callee(str.substring(1, len - 1)) + str[0];
+      }
+      return str;
+    }
+  };
+}());

javascript/lib/data-structures/chapter-1/1_3.js

@@ -0,0 +1,31 @@
+module.exports = Strings_1_3 = (function() {
+  return {
+    // Tests to see if two strings are permutations of one another
+    // Solution #2 from the book. Assumes ascii character set
+    // @param {String} s - The first string
+    // @param {String} t - The second string
+    // @retuns {Boolean} - true if the strings are permutations of one another, false otherwise
+    isPermutation: function(s, t) {
+
+      var sLength = s.length;
+      var tLength = t.length;
+
+      if (sLength !== tLength) {
+        return false;
+      }
+
+      var s_array = Array.apply(null, Array(256)).map(Number.prototype.valueOf, 0);
+
+      for (var i = 0; i < sLength; i++) {
+        s_array[s[i].charCodeAt(0)]++;
+      }
+
+      for (var i = 0; i < tLength; i++) {
+        if (--s_array[t[i].charCodeAt(0)] < 0){
+          return false;
+        }
+      }
+      return true;
+    }
+  };
+}());