freeCodeCamp Challenge Guide: ABC Problem

ABC Problem


Solution 1 - (Click to show/hide)
function canMakeWord(word) {
  const blocksArr = [
    ["B", "O"], ["X", "K"], ["D", "Q"], ["C", "P"], ["N", "A"],
    ["G", "T"], ["R", "E"], ["T", "G"], ["Q", "D"], ["F", "S"],
    ["J", "W"], ["H", "U"], ["V", "I"], ["A", "N"], ["O", "B"],
    ["E", "R"], ["F", "S"], ["L", "Y"], ["P", "C"], ["Z", "M"],
  word = word.toUpperCase().split("");

  for (let letter in word) {
    // Check if any block contains letter
    const blockIndex = blocksArr.findIndex(
      (block) => block.indexOf(word[letter]) >= 0
    if (blockIndex == -1) {
      // Return false if no blocks contains letter
      return false;
    } else {
      // Otherwise, remove the block
      blocksArr.splice(blockIndex, 1);
  return true;

Code Explanation

The function is case-insensitive, so the argument is converted to an array of uppercase letters.
We loop through our word array in order to test each letter separately.
For each letter, we check for a block which can represent the letter.
If the letter is present in a block, we delete the block so it cannot be reused.
We return false early if no block matches the letter, otherwise we complete our loop and return true.

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