function stringToZigzagGrid(text: string, numRows: number): string[][] | string {
    if (numRows < 2) return text

    const grid: string[][] = Array.from({ length: numRows }, () => [])

    let row = 0, col = 0, direction = "down"

    for (let index = 0; index < text.length; index++) {
        grid[row][col] = text[index]

        if (row === numRows - 1) {
            direction = "up"
        } else if (row === 0) {
            direction = "down"
        }

        if (direction === "down") {
            row++
        } else {
            col++
            row--
            for (let r = 0; r < numRows; r++) {
                if (!grid[r][col]) grid[r][col] = " ";
            }

        }
    }
    return grid
}
      
console.log(stringToZigzagGrid("PAYPALISHIRING", 4))