Solved JS Functions & Arrays lab

src/functions-and-arrays.js

@@ -1,41 +1,65 @@
 // Iteration #1: Find the maximum
-function maxOfTwoNumbers() {}
+function maxOfTwoNumbers(a, b) {
+  return a > b ? a : b;
+}
+
 
 
 
 // Iteration #2: Find longest word
 const words = ['mystery', 'brother', 'aviator', 'crocodile', 'pearl', 'orchard', 'crackpot'];
 
-function findLongestWord() {}
+function findLongestWord(words) {
+  if (words.length === 0) return null;
+  return words.reduce((longest, word) => word.length > longest.length ? word : longest, words[0]);
+}
 
 
 
 // Iteration #3: Calculate the sum
 const numbers = [6, 12, 1, 18, 13, 16, 2, 1, 8, 10];
 
-function sumNumbers() {}
+function sumNumbers(numbers) {
+  return numbers.reduce((sum, num) => sum + num, 0);
+}
 
 
 
 // Iteration #3.1 Bonus:
-function sum() {}
+function sum(arr) {
+  return arr.reduce((total, item) => {
+    if (typeof item === 'number') return total + item;
+    if (typeof item === 'string') return total + item.length;
+    if (typeof item === 'boolean') return total + (item ? 1 : 0);
+    return total;
+  }, 0);
+}
 
 
 
 // Iteration #4: Calculate the average
 // Level 1: Array of numbers
 const numbersAvg = [2, 6, 9, 10, 7, 4, 1, 9];
-
-function averageNumbers() {}
+function averageNumbers(numbersAvg) {
+  if (numbers.length === 0) return null;
+  return sumNumbers(numbers) / numbers.length;
+}
 
 
 // Level 2: Array of strings
 const wordsArr = ['seat', 'correspond', 'linen', 'motif', 'hole', 'smell', 'smart', 'chaos', 'fuel', 'palace'];
 
-function averageWordLength() { }
+function averageWordLength(wordsArr) {
+  if (words.length === 0) return null;
+  return sum(words) / words.length;
+}
+
 
 // Bonus - Iteration #4.1
-function avg() {}
+function avg(arr) {
+  if (arr.length === 0) return null;
+  return sum(arr) / arr.length;
+}
 
 // Iteration #5: Unique arrays
 const wordsUnique = [
@@ -52,14 +76,18 @@ const wordsUnique = [
   'bring'
 ];
 
-function uniquifyArray() {}
+function uniquifyArray(wordsUnique) {
+  return words.length === 0 ? null : [...new Set(words)];
+}
 
 
 
 // Iteration #6: Find elements
 const wordsFind = ['machine', 'subset', 'trouble', 'starting', 'matter', 'eating', 'truth', 'disobedience'];
 
-function doesWordExist() {}
+function doesWordExist(wordsFind, word) {
+  return wordsFind.length === 0 ? null : wordsFind.includes(word);
+}
 
 
 
@@ -78,7 +106,9 @@ const wordsCount = [
   'matter'
 ];
 
-function howManyTimes() {}
+function howManyTimes(wordsCount, word) {
+  return wordsCount.filter(w => w === word).length;
+}
 
 
 
@@ -106,9 +136,38 @@ const matrix = [
   [1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48]
 ];
 
-function greatestProduct() {}
+function greatestProduct(matrix) {
+  let maxProduct = 0;
+
+  for (let i = 0; i < matrix.length; i++) {
+    for (let j = 0; j < matrix[i].length; j++) {
+      if (j < matrix[i].length - 3) {
+        let horizontal = matrix[i][j] * matrix[i][j + 1] * matrix[i][j + 2] * matrix[i][j + 3];
+        maxProduct = Math.max(maxProduct, horizontal);
+      }
+      if (i < matrix.length - 3) {
+        let vertical = matrix[i][j] * matrix[i + 1][j] * matrix[i + 2][j] * matrix[i + 3][j];
+        maxProduct = Math.max(maxProduct, vertical);
+      }
+    }
+  }
+  return maxProduct;
+}
 
 
+// Bonus - Iteration #8.1: Product of diagonals
+function greatestProductOfDiagonals(matrix) {
+  let maxProduct = 0;
+
+  for (let i = 0; i < matrix.length - 3; i++) {
+    for (let j = 0; j < matrix[i].length - 3; j++) {
+      let diag1 = matrix[i][j] * matrix[i + 1][j + 1] * matrix[i + 2][j + 2] * matrix[i + 3][j + 3];
+      let diag2 = matrix[i][j + 3] * matrix[i + 1][j + 2] * matrix[i + 2][j + 1] * matrix[i + 3][j];
+      maxProduct = Math.max(maxProduct, diag1, diag2);
+    }
+  }
+  return maxProduct;
+}
 
 
 // The following is required to make unit tests work.