python课程作业——Leetcode 6. ZigZag Conversion

Description

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);

Solution

直接模拟即可。注意特判numRows == 1的情况

Code

class Solution:
    def convert(self, s, numRows):
        """
        :type s: str
        :type numRows: int
        :rtype: str
        """
        if numRows == 1:
            return s

        arr = [''] * numRows
        i = 0
        di = 1
        for c in s:
            arr[i] += c
            if di > 0:
                if i == numRows - 1:
                    di = -1
            else:
                if i == 0:
                    di = 1
            i += di

        res = ""
        for row in arr:
            res += row

        return res


sol = Solution()
print(sol.convert('ABC', 1))