6. Zigzag Conversion

The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)

P A H N
A P L S I I G
Y I R

And then read line by line: "PAHNAPLSIIGYIR"

Write the code that will take a string and make this conversion given a number of rows:

string convert(string s, int numRows);

Example 1:

Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"

Example 2:

Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"
Explanation:
P I N
A L S I G
Y A H R
P I

Example 3:

Input: s = "A", numRows = 1
Output: "A"

def convert(self, s: str, numRows: int) -> str:
	if numRows == 1 or numRows >= len(s):
		return s
	rows = [''] * numRows
	curr_row = 0
	going_down = False
	
	for char in s:
		rows[curr_row] += char
		if curr_row == 0 or curr_row == numRows - 1:
			going_down = not going_down
		curr_row += 1 if going_down else -1
	
	return ''.join(rows)