Leet Code 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"

 

Constraints:

• 1 <= s.length <= 1000
• s consists of English letters (lower-case and upper-case), ',' and '.'.
• 1 <= numRows <= 1000

import numpy as np

class Solution(object):

    def convert(self, s, numRows):

        numCols = len(s)

        arr_characters = np.zeros(numRows * numCols).reshape(numRows, numCols)

        #print(arr_characters)

        if numRows == 1:

            return s

        else:

            counter = 0

            pos = 0

            vertical_shift = 0

            for i in range(len(s)):

                if counter <= numRows:

                    _zero = 0

                    for j in range(numRows):

                        if pos >= len(s):

                            break

                        else:

                            #print(s[pos],end=' ')

                            #print("(",_zero,vertical_shift,")",end= ' ') # = ord(s[pos])

                            arr_characters[_zero][vertical_shift] = ord(s[pos])

                            pos += 1

                            _zero += 1

                    counter = numRows + 1

                    vertical_shift += (numRows - 1)

                    #print(vertical_shift,"***************")

                else:

                    diagonal_shift_col = vertical_shift - (numRows - 2)

                    diagonal_shift_row = numRows - 2

                    for j in range(numRows - 2):

                        if pos >= len(s):

                            break

                        else:

                            #print(s[pos],end = ' ')

                            #print("(",diagonal_shift_row,diagonal_shift_col,")",end= ' ') # = ord(s[pos])

                            arr_characters[diagonal_shift_row][diagonal_shift_col] = ord(s[pos])

                            diagonal_shift_col += 1

                            diagonal_shift_row -= 1

                            pos += 1

                    #print("**************")

                    counter = 0

            #print(arr_characters)

            output = ""

            for i in range(numRows):

                for j in range(numCols):

                    if arr_characters[i][j] != 0:

                        output += chr(int(arr_characters[i][j]))

                    else:

                        output += ""

            #output.encode('utf-8')

            return output

obj = Solution()

s = ""

numRows = int(input("Enter the number of rows:"))

s = str(input("Enter the string:"))

print(obj.convert(s, numRows))