ZigZag Conversion

发表于   |   分类于   |   阅读次数

ZigZag Conversion

orignal problem description

problem

1
2
3
4
5
6
7
8
9
10
11
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

1
2
Input: s = "PAYPALISHIRING", numRows = 3
Output: "PAHNAPLSIIGYIR"

Example 2

1
2
3
4
5
6
7
8
Input: s = "PAYPALISHIRING", numRows = 4
Output: "PINALSIGYAHRPI"
Explanation:

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

answer

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
class Solution:
    def convert(self, s, numRows):
        """
        :type s: str
        :type numRows: int
        :rtype: str
        """
        row_values = [""]*numRows
        s_length = len(s)
        
        
        if numRows == 1:
            print("".join(row_values))
            return s
        
        for index, value in enumerate(row_values):
            length = index
            mark = 1
            while length < s_length:
                if index != 0 and index != (numRows-1):
                    row_values[index] += s[length]
                    if mark == 1 :
                        length += (numRows - index-1)*2
                    elif mark == 2:
                        length += (index)*2
                    mark = 2/mark
                else:
                    row_values[index] += s[length]
                    length += (numRows-1)*2
        print("".join(row_values))
        return "".join(row_values)