Snail Traversal

declare global {
  interface Array<T> {
    snail(rowsCount: number, colsCount: number): T[][];
  }
}
 
Array.prototype.snail = function (rowsCount: number, colsCount: number) {
  if (this.length !== rowsCount * colsCount) {
    return [];
  }
  const arr = Array.from({ length: rowsCount }).map(() => new Array(colsCount).fill(0));
 
  for (let col = 0; col < colsCount; col++) {
    for (let row = 0; row < rowsCount; row++) {
      if (col % 2 === 0) {
        arr[row][col] = this[col * rowsCount + row];
      } else {
        arr[rowsCount - row - 1][col] = this[col * rowsCount + row];
      }
    }
  }
 
  return arr;
};
 
export {};