leetcode 6. ZigZag Conversion

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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 conversion 解题关键点在于寻找循环，（2 * nRows - 2）个字符构成一个循环。

 1     string convert(string s, int nRows) 
 2     {
 3         string *st = new string[nRows];
 4         int k, i;
 5         if (nRows <= 1)
 6             return s;
 7             
 8         for (i = 0; i < s.length(); i++)
 9         {
10             k = i % (2 * nRows - 2);
11             if (k >= (nRows - 1))
12                 st[2 * (nRows - 1) - k] += s[i];
13             else
14                 st[k] += s[i];
15         }
16         
17         s = "";
18         for (i = 0; i < nRows; i++)
19             s += st[i];
20             
21         return s;
22     }

leetcode 6. ZigZag Conversion

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原文地址：http://www.cnblogs.com/ym65536/p/4082437.html