DimwittedLovelyAdware created by anonymous - https://repl.it/repls/DimwittedLovelyAdware

DimwittedLovelyAdware.js

assertEquality = (actual, expected, description) => {
  if (actual === expected) {
    console.log("It should..." + description + '...PASS!')
  } else {
    console.log("It should..." + description + "...FAIL\n...expected: '" + expected + "' but got: '" + actual + "' instead.")
  }
}

assertEquality(true, true, "assert equality")


// 1
// 11

// 21
// 1211
// 111221

lookAndSay = (num) => {

  // initialize value as 1
  let value = 1;
  // loop through from 1 up until the input number
  for (let i = 1; i <= num; i++) {
    // each time print out value
    // reassign value to the output value of reading the last value
    console.log(value);
    value = newOutputValue(value);
  }
}

newOutputValue = (input) => {
  input = input.toString();
  if (input.length === 1) {
    return `1${input}`;
  }
  // two pointers
  // initialize count at 1
  let returnString = "";
  let current = input[0];
  let count = 1;

  for (let j = 1; j <= input.length; j++) {
    // if the next number doesn't equal the current one
    // or its the last character in the string
    if (current !== input[j] || j === input.length) {
      // put the count and the number in the return string
      // reset count and increment the current pointer
      returnString += `${count}${current}`;
      count = 1;
      current = input[j];
    } else {
      // otherwise they are the same, just count it
      count++;
    }
  }
  return returnString;
}


// console.log(lookAndSay(5))
// console.log(lookAndSay(10))


function oneEditApart(str1, str2) {

  if (str1.length !== str2.length) {
    let idx1 = 0, idx2 = 0;
    let diff = 0;
    while (idx1 <= str1.length && idx2 <= str2.length) {
      if (str1[idx1] !== str2.length) {
        diff++;
      }
      idx1++;
      idx2++;
    }
    if (Math.abs(idx1 - idx2) > 1) {
      return false
    }
  } else {
    let diff = 0;
    for (let i = 0; i < str1.length; i++) {
      if (str1[i] !== str2[i]) {
        diff++;
      }

      if (diff >= 2) {
        return false
      }
    }
  }

  return true;
}

assertEquality(oneEditApart("cat", "dog"), false, 'tell if "cat" and "dog" are one edit apart');
assertEquality(oneEditApart("cat", "cats"), true, 'tell if "cat" and "cats" are one edit apart');
assertEquality(oneEditApart("cat", "cut"), true, 'tell if "cat" and "cut" are one edit apart');
assertEquality(oneEditApart("cat", "cast"), true, 'tell if "cat" and "cast" are one edit apart');
assertEquality(oneEditApart("cat", "at"), true, 'tell if "cat" and "at" are one edit apart');
assertEquality(oneEditApart("cat", "act"), false, 'tell if "cat" and "act" are one edit apart');


/*
  Spiral: 

  Find the pattern and complete the function: 
  int[][] spiral(int n);
  where n is the size of the 2D array.

input = 3
123
894
765

input = 4
01 02 03 04
12 13 14 05
11 16 15 06
10 09 08 07

input = 8
1 2 3 4 5 6 7 8
28 29 30 31 32 33 34 9
27 48 49 50 51 52 35 10
26 47 60 61 62 53 36 11
25 46 59 64 63 54 37 12
24 45 58 57 56 55 38 13
23 44 43 42 41 40 39 14
22 21 20 19 18 17 16 15

 */

function getSpiral(n) {
  if (n <= 0) {
    throw new Error("N must be greater than 0");
  }

  let dc = [ 1, 0, -1, 0 ];
  let dr = [ 0, 1, 0, -1 ];
  let dir = 0, value = 0, row = 0, column = 0, limit = n*n;
  let matrix = [...Array(n)].map(x => new Array(n).fill(0));

  while (value++ < limit) {
    matrix[row][column] = value;
    console.log('added: ', value, 'to row:', row, 'and column', column )
    row += dr[dir];
    column += dc[dir];
    if (isInvalid(matrix, row, column)) {
      console.log('is invalid', row, column)
      row -= dr[dir];
      column -= dc[dir];
      console.log('readjust:', row, column)
      dir = (dir+1) % 4;
      console.log('dir', dir)
      row += dr[dir];
      column += dc[dir];
      console.log('new coord: ', row, column)
    }
  }

  return matrix;
}

function isInvalid(matrix, row, column) {
  return row < 0 || column < 0 || row >= matrix.length || column >= matrix.length || matrix[row][column] !== 0; 
}

console.log(getSpiral(4));

/*
transpose matrix: 

input: 2d Array matrix 
output: transposed 2d Array matrix

- iterate through 1/2 of rows
  - for each row, iterate through columns
    - 4 way swap with same position 90 degrees clockwise
      - use temp var
      - i, j => j, n-i-1 => n-i-1, n-j-1 => n-j-1, i
- return matrix

*/

transposeMatrix = (matrix) => {
  let n = matrix.length;

  for (let i = 0; i < n/2; i++) {

    for (let j = i; j < n-i-1; j++) {

      let temp = matrix[i][j];
      matrix[i][j] = matrix[n-j-1][i];
      matrix[n-j-1][i] = matrix[n-i-1][n-j-1];
      matrix[n-i-1][n-j-1] = matrix[j][n-i-1];
      matrix[j][n-i-1] = temp;
    }
  }

  return matrix;
}

const matrix1 = [ [ 1, 2, 3, 4, 5 ],
                  [ 6, 7, 8, 9, 10],
                  [ 11, 12, 13, 14, 15],
                  [ 16, 17, 18, 19, 20],
                  [ 21, 22, 23, 24, 25]]

console.log(transposeMatrix(matrix1))