leetcode - ZigZag Conversion

转自：/article/6347759.html

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"

Zigzag:即循环对角线结构（

0				8				16
1			7	9			15	17
2		6		10		14		18
3	5			11	13			19
4				12				20

）

nRows行，声明nRows个字符串，每个字符串存储自己行的字符

向下循环:nRows

斜角线向上循环: 从nRows-2 开始，1 结束 (减去首尾两个端点)

重复

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