distance.ts

export function distance(a: string, b: string): number {
  if (a.length == 0) {
    return b.length;
  }
  if (b.length == 0) {
    return a.length;
  }
  const matrix = [];
  for (let i = 0; i <= b.length; i++) {
    matrix[i] = [i];
  }
  for (let j = 0; j <= a.length; j++) {
    matrix[0][j] = j;
  }
  for (let i = 1; i <= b.length; i++) {
    for (let j = 1; j <= a.length; j++) {
      if (b.charAt(i - 1) == a.charAt(j - 1)) {
        matrix[i][j] = matrix[i - 1][j - 1];
      } else {
        matrix[i][j] = Math.min(
          matrix[i - 1][j - 1] + 1,
          Math.min(matrix[i][j - 1] + 1, matrix[i - 1][j] + 1),
        );
      }
    }
  }
  return matrix[b.length][a.length];
}