jan20-lab-javascript-functions-and-arrays-solution.js

// Iteration #1: Find the maximum

function maxOfTwoNumbers(a, b) {
  if (a > b) return a;
  return b;
}

// Iteration #2: Find longest word

const words = ['mystery', 'brother', 'aviator', 'crocodile', 'pearl', 'orchard', 'crackpot'];

function findLongestWord(arrayOfWords) {
  if (arrayOfWords.length === 0) {
    return null;
  }
  let longestWord;
  for (let word of arrayOfWords) {
    if (typeof longestWord === 'undefined' || word.length > longestWord.length) {
      longestWord = word;
    }
  }
  return longestWord;
}

// Iteration #3: Calculate the sum

const numbers = [6, 12, 1, 18, 13, 16, 2, 1, 8, 10];

function sumArray(arrayOfNumbers) {
  let sum = 0;
  for (let number of arrayOfNumbers) {
    sum += number;
  }
  return sum;
}

// Iteration #4: Calculate the average

// Level 1: Array of numbers

const numbersAvg = [2, 6, 9, 10, 7, 4, 1, 9];

function averageNumbers(arrayOfNumbers) {
  if (arrayOfNumbers.length === 0) {
    return null;
  }
  const sum = sumArray(arrayOfNumbers);
  const average = sum / arrayOfNumbers.length;
  return average;
}
// Level 2: Array of strings

const wordsArr = [
  'seat',
  'correspond',
  'linen',
  'motif',
  'hole',
  'smell',
  'smart',
  'chaos',
  'fuel',
  'palace'
];

function averageWordLength(arrayOfWords) {
  if (!arrayOfWords.length) return null;
  const numberOfWords = arrayOfWords.length;
  let totalLength = 0;
  for (let word of arrayOfWords) {
    totalLength += word.length;
  }
  const averageLength = totalLength / numberOfWords;
  return averageLength;
}

// Iteration #5: Unique arrays
const wordsUnique = [
  'crab',
  'poison',
  'contagious',
  'simple',
  'bring',
  'sharp',
  'playground',
  'poison',
  'communion',
  'simple',
  'bring'
];

function uniquifyArray(arrayOfWords) {
  const arrayOfUniques = [];
  for (let word of arrayOfWords) {
    if (arrayOfUniques.indexOf(word) < 0) {
      arrayOfUniques.push(word);
    }
  }
  return arrayOfUniques;
}

// Iteration #6: Find elements

const wordsFind = [
  'machine',
  'subset',
  'trouble',
  'starting',
  'matter',
  'eating',
  'truth',
  'disobedience'
];

function doesWordExist(arrayOfWords, word) {
  for (let occurrence of arrayOfWords) {
    if (occurrence === word) return true;
  }
  return false;
}

// Iteration #7: Count repetition

const wordsCount = [
  'machine',
  'matter',
  'subset',
  'trouble',
  'starting',
  'matter',
  'eating',
  'matter',
  'truth',
  'disobedience',
  'matter'
];

function howManyTimes(arrayOfWords, word) {
  let count = 0;
  for (let occurrence of arrayOfWords) {
    if (occurrence === word) count++;
  }
  return count;
}

// Iteration #8: Bonus

const matrix = [
  [8, 2, 22, 97, 38, 15, 0, 40, 0, 75, 4, 5, 7, 78, 52, 12, 50, 77, 91, 8],
  [49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48, 4, 56, 62, 0],
  [81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30, 3, 49, 13, 36, 65],
  [52, 70, 95, 23, 4, 60, 11, 42, 69, 24, 68, 56, 1, 32, 56, 71, 37, 2, 36, 91],
  [22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80],
  [24, 47, 32, 60, 99, 3, 45, 2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50],
  [32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70],
  [67, 26, 20, 68, 2, 62, 12, 20, 95, 63, 94, 39, 63, 8, 40, 91, 66, 49, 94, 21],
  [24, 55, 58, 5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72],
  [21, 36, 23, 9, 75, 0, 76, 44, 20, 45, 35, 14, 0, 61, 33, 97, 34, 31, 33, 95],
  [78, 17, 53, 28, 22, 75, 31, 67, 15, 94, 3, 80, 4, 62, 16, 14, 9, 53, 56, 92],
  [16, 39, 5, 42, 96, 35, 31, 47, 55, 58, 88, 24, 0, 17, 54, 24, 36, 29, 85, 57],
  [86, 56, 0, 48, 35, 71, 89, 7, 5, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58],
  [19, 80, 81, 68, 5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77, 4, 89, 55, 40],
  [4, 52, 8, 83, 97, 35, 99, 16, 7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66],
  [88, 36, 68, 87, 57, 62, 20, 72, 3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69],
  [4, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18, 8, 46, 29, 32, 40, 62, 76, 36],
  [20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74, 4, 36, 16],
  [20, 73, 35, 29, 78, 31, 90, 1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57, 5, 54],
  [1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52, 1, 89, 19, 67, 48]
];

function greatestProduct(matrix) {
  let greatest;

  // CHECK COMBINATIONS HORIZONTALY
  for (let r = 0; r < matrix.length; r++) {
    for (let i = 0; i < matrix[r].length - 4 + 1; i++) {
      const product = matrix[r][i] * matrix[r][i + 1] * matrix[r][i + 2] * matrix[r][i + 3];
      if (typeof greatest === 'undefined' || product > greatest) {
        greatest = product;
      }
    }
  }

  // CHECK COMBINATIONS VERTICALY
  for (let c = 0; c < matrix[0].length; c++) {
    for (let i = 0; i < matrix.length - 4 + 1; i++) {
      const product = matrix[i][c] * matrix[i + 1][c] * matrix[i + 2][c] * matrix[i + 3][c];
      if (typeof greatest === 'undefined' || product > greatest) {
        greatest = product;
      }
    }
  }

  return greatest;
}