removed comments

chapter08/8.01 - Triple Step/tripleStep.js

@@ -1,65 +1,30 @@
-/*
-Recursion and Dynamic Programming (4 steps)
-1. Start with the recursive backtracking solution 
-2. Optimize by using a memoization table (top-down dynamic programming) 
-3. Remove the need for recursion (bottom-up dynamic programming) 
-4. Apply final tricks to reduce the time / memory complexity
-*/
-
-/*
-Triple Step: 
-A child is running up a staircase with n steps and 
-can hop either 1 step, 2 steps, or 3 steps at a time. 
-
-Implement a method to count how many possible ways 
-the child can run up the stairs.
- */
-
-
-var numWays = function(N) { 
-  var answer = 0;
-  var recurse = function(number) {
-    if (number === 0) {
-      answer++;
-    } else if (number > 0) {
-      recurse(number - 1);
-      recurse(number - 2);
-      recurse(number - 3);
-    }
-  };
-  recurse(N);
-  return answer;
-};
-
 // Recursive BackTracking 
 // Time & Space O(n!)
-/*
-var numWays = function(n, res=0) {
+var tripleStep = function(n, res=0) {
   if (n < 0) return 0
   if (n === 0)  {
     res++
     return res
   }
-  return numWays(n - 1) + numWays(n - 2) + numWays(n - 3)
+  return tripleStep(n - 1) + tripleStep(n - 2) + tripleStep(n - 3)
 }
-*/
 
 // Top Down Memoization
 // Time & Space O(n)
 /*
-var numWays = function(n, i=3, memo = [1, 1, 2, 4]) {
+var tripleStep = function(n, i=3, memo = [1, 1, 2, 4]) {
   if (n < 0) return memo[0]
   if (n === 1) return memo[n]
   if (i > n ) return memo[memo.length - 1]
   memo[i] = memo[i - 1] + memo[i - 2] + memo[i - 3]
-  return numWays(n, i+1, memo)
+  return tripleStep(n, i+1, memo)
 }
 */
 
 // Bottom Up memoization
 // Time & Space O(n) 
 /*
-var numWays = function(n, memo=[1,1,2,4]) {
+var tripleStep = function(n, memo=[1,1,2,4]) {
 
   for (let i = 3; i <= n; i++) {
     memo[i] = memo[i - 1] + memo[i - 2] + memo[i - 3]
@@ -69,13 +34,11 @@ var numWays = function(n, memo=[1,1,2,4]) {
 }
 */
 
-
 /* TEST */
-
-console.log(numWays(1), 1);
-console.log(numWays(2), 2);
-console.log(numWays(3), 4);
-console.log(numWays(5), 13)
-console.log(numWays(7), 44)
-console.log(numWays(10), 274);
+console.log(tripleStep(1), 1);
+console.log(tripleStep(2), 2);
+console.log(tripleStep(3), 4);
+console.log(tripleStep(5), 13)
+console.log(tripleStep(7), 44)
+console.log(tripleStep(10), 274);