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   NA P L S I I GY   I   RAnd 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".
zigzag 是什么意思捏：
row=4     06
  15 7
                  24 8
  39
就是這樣子的格式
python 代碼：
class Solution(object):    def convert(self, s, numRows):        """        :type s: str        :type numRows: int        :rtype: str        """        l=[]        for i in range(numRows):            l.append("")        num=numRows*2-2                for i,j in enumerate(s):            if num==0:                return s            elif i%num<numRows:                index=i%num                l[index] +=j            else:                index -=1                l[index] += j        return "".join(l)還看到一位大神的代碼，比我的高明多了。。。。
比numrow小,index 加一，其他減一