Function oneAway

strings/one-away.js:48–76

(array1, array2)

// Time O(n + m)
// Space O(max(n + m))
function oneAway(array1, array2) {
  const largerString = array1.length > array2.length ? array1 : array2;
  const smallString = array1.length <= array2.length ? array1 : array2;
  const frequencies = {};
  let edits = 0;

  if (largerString.length - smallString.length > 1) return false;

  for (let i = 0; i < largerString.length; i++) {
    if (frequencies.hasOwnProperty(largerString[i])) {
      frequencies[largerString[i]]++;
    } else {
      frequencies[largerString[i]] = 1;
    }
  }

  for (let j = 0; j < smallString.length; j++) {
    if (frequencies.hasOwnProperty(smallString[j])) {
      if (frequencies[smallString[j]] === 0) return false;
      frequencies[smallString[j]] -= 1;
    }
  }

  Object.values(frequencies).forEach((value) => {
    edits += value;
  });

  return edits <= 1;
}

console.log(oneAway("pale", "ple"));
console.log(oneAway("pale", "pales"));