class Solution(object):
    def convert(self, s, numRows):
        if numRows == 1:
            return s 
        n = len(s)
        cycle = 2*numRows - 2
        strlist = []
        for i in range(numRows):
            for j in range(i, n, cycle):
                strlist.append(s[j])
                if i != numRows - 1 and i != 0 and j + cycle - 2*i < n:
                    strlist.append(s[j + cycle - 2*i])             
        newstr = ''.join(strlist)
        return newstr
        
        
"""
6. ZigZag Conversion
Medium

1239

3740

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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
"""
