6. ZigZag Conversion Leetcode Python

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 text, int nRows);

convert("PAYPALISHIRING", 3) should return "PAHNAPL

SIIGYIR".

这题的主要特点是要观察出新序列的位置为 2*nRows-2

代码如下

class Solution:
    # @return a string
    def convert(self, s, nRows):
        if nRows==1:
            return s
        if len(s)<=1:
            return s
        n=nRows
        size=2*n-2
        result=[]
        for i in range(n):
            j=i
            while j<len(s):
                result.append(s[j])
                if i!=0 and i!=n-1 and j+size-2*i<len(s):
                    result.append(s[j+size-2*i])
                j+=size
        return "".join(result)