Merge remote-tracking branch 'upstream/master'

Author: rroque98

JavaScript/chapter01/1.1 - Is Unique/solution.js

@@ -4,9 +4,7 @@ Output: returns a deduped array of integers
 */
 
 // Solution using Set 
-
 const isUnique = (arr) => [...new Set(arr)];
 
 // Test Cases
-
 console.log(isUnique([1,1,1,2,2,2,2,3,3,3,3]) === [1,2,3]); 

JavaScript/chapter01/1.2 - Check Perm/solution.js

@@ -0,0 +1,15 @@
+/* Given two strings, write a method to decide 
+if one is permutation of the other */
+
+var checkPerm = function(stringOne,  stringTwo) {
+    //if different lengths, return false
+    if (stringOne.length !==  stringTwo.length ) {
+        return false; 
+    } 
+    //else sort & compare
+    else {
+        var sortStringOne = stringOne.split('').sort('').join('');
+        var sortStringTwo = stringTwo.split('').sort('').join('');
+        return sortStringOne === sortStringTwo;
+    }
+};

JavaScript/chapter01/1.3 - URLify/solution.js

@@ -23,8 +23,10 @@ function URLify(arr, len) {
 
 //testing
 let arr = ['M', 'r', ' ', 'J', 'o', 'h', 'n', ' ', 'S', 'm', 'i', 't', 'h', ' ', ' ', ' ', ' '];
+
 //before
 console.log(arr);
 let ans = URLify(arr, 13);
+
 //after
 console.log(ans);

JavaScript/chapter01/1.9 - String Rotation/solution.js

@@ -0,0 +1,13 @@
+/* Assume you have a method isSubstring which checks if one word is a substring
+of another. Given two strings, sl and s2, write code to check if s2 is a rotation of sl using only one
+call to isSubstring (e.g., "waterbottle" is a rotation of"erbottlewat") */
+
+var StringRotate = function(string1, string2) {
+    if (string1.length !== string2.length ){
+        return false; 
+    }
+    return ( string2 + string1 ).includes(string1); // one call of Substring
+};
+
+//Test 
+console.log(StringRotate('waterbottle', 'erbottlewat'), true);

JavaScript/chapter02/2.2 - Return Kth to Last/solution.js

@@ -0,0 +1,40 @@
+/* Return Kth to Last: Implement an algorithm to find the kth to last element of a singly linked list. */
+
+var linkedList = function(value) {
+    this.value = value; 
+    this.next = null; 
+};
+
+var findKthToLast = function(k, head) {
+    //do recursive
+    if ( head == null || k < 1 ) {
+        return;
+    } else if ( k == 1 ) {
+        console.log(head.value);
+        findKthToLast(k, head.next)
+    } else {
+        findKthToLast( k-1, head.next);
+    }
+};
+
+/* Tests */ 
+var a = new linkedList('1');
+var b = new linkedList('2');
+var c = new linkedList('3');
+var d = new linkedList('4');
+var e = new linkedList('5');
+var f = new linkedList('6');
+var g = new linkedList('7');
+
+a.next = b;
+b.next = c;
+c.next = d;
+d.next = e;
+e.next = f;
+f.next = g;
+
+findKthToLast(3, a);
+findKthToLast(10, a);
+findKthToLast(-1, a);
+findKthToLast(0, a);
+findKthToLast(1, a);