题目

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 “PAHNAPLSIIGYIR”.

• 大意：把给定的一个字符串，写成指定行数的N字形（ZigZag形），然后从左到右读成新的字符串：
  

思路和吐槽

这道题还是没有什么高深的，只是要去找规律，推通式，我再次鄙视下自己的智商。

##代码
###Python

class Solution(object):
    def convert(self, s, numRows):
<!--more-->
        """
        :type s: str
        :type numRows: int
        :rtype: str
        """
        max_index = len(s)
        ans = []
        T = 2 * (numRows - 1)
        if numRows == 1 or max_index <= numRows:
            return s
        i = 0
        while(True):
            if i == 0:
                j = 0
                while(True):
                    if j * T + i < max_index:
                        ans.append(s[j * T + i])
                        j += 1
                    else:
                        break
            elif i == numRows - 1:
                j = 0
                while(True):
                    if j * T + i < max_index:
                        ans.append(s[j * T + i])
                        j += 1
                    else:
                        break
                ans_str = ''.join(ans);
                return ans_str
            else:
                j = 0
                while(True):
                    if j * T + i < max_index:
                        ans.append(s[j * T + i])
                    else:
                        break
                    if (j + 1) * T - i < max_index:
                        ans.append(s[(j + 1) * T - i])
                    else:
                        break
                    j += 1
            i = i + 1
            print i