chapter 4 and chapter 5

chapter04.js

@@ -8,38 +8,75 @@
 
 
 // Problem 1: The sum of a range
-function range(start, end, step=1) {
-  // Your code here
+function range(start, end, inc=1) {
+  var array = [];
+  if(start <= end){
+    for (var i=start; i<= end; i+= inc){
+      array.push(i);
+    }
+  }
+  else{
+    for(var x = start; x>= end; x-=inc){
+      array.push(x);
+    }
+  }
+  return array;
 }
 
-function sum(array) {
-  // Your code here
+function sum(arr) {
+  var total = 0;
+  for(var i=0; i< arr.length; i++){
+    total += arr[i];
+  }
+  return total; 
 }
 
 // Problem 2: Reversing an Array
-function reverseArray(array) {
-  // Your code here
+function reverseArray(arr) {
+  var new_arr = []; 
+  for(var i = arr.length -1; i>= 0; i--){
+    new_arr.push(arr[i]);
+  }
+  return new_arr;
 }
 
-function reverseArrayInPlace(array) {
-  // Your code here
+function reverseArrayInPlace(arr) {
+for(var x = 0; x< Math.floor(arr.length/2);x++){
+    var tmp = arr[x];
+    arr[x] = arr[arr.length -1- x];
+    arr[arr.length-1-x] = tmp;
+  }
+  return arr;
 }
 
 // Problem 3: A List
-function arrayToList(array) {
-  // Your code here
+function arrayToList(arr) {
+  var list = null; // not [] bc it's not an array!!
+  for(var i = arr.length -1 ; i >= 0; i--){
+    list = {value: arr[i], rest: list}
+  }
+  return list;
 }
 
 function listToArray(list) {
-  // Your code here
+ arr = []; // we need this in order to create new array
+  for(var node= list; node; node = node.rest){
+    arr.push(node.value);
+  }
+  return arr;
 }
 
 function nth(list, position) {
-  // Your code here
+  for(var node = list; node; node = node.rest){
+    var tmp = listToArray(node);
+  }
+  return tmp[node]; 
+
 }
 
 function prepend(element, list) {
-  // Your code here
+  list = {value: element, rest: list};
+  return list;
 }
 
 // Problem 4: Deep comparison

chapter05.js

@@ -20,15 +20,24 @@ ancestry.forEach(function(person) {
 
 // Problem 1: Flattening
 function flatten(arrays) {
-  // Your code here
-}
+  arr.reduce(function(curr, next){return curr.concat(next)});
 
 // Problem 2: Mother-child age difference
 /* This must return the average age difference instead of printing it */
+var byName = {};
+ancestry.forEach(function(person) {
+  byName[person.name] = person;
+});
+
+function hadKnownMother(person){
+	return person.mother in byName;
+}
+
 function averageMomChildAgeDiff() {
-  // Your code here
+  return person.born - byName[person.mother].born;
 }
 
+
 // Problem 3: Historical life expectancy
 /* This must return the object/map with centuries as keys and average age
     for the century as the value