LeetCode 6 - ZigZag Conversion

原题如下：

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".

实现思路比较简单直白，直接上代码吧：

 1     public String convert(String s, int nRows) {
 2         int len = s.length();
 3         if(nRows >= len || nRows == 1){
 4             return s;
 5         }
 6         StringBuilder sb = new StringBuilder();
 7         for(int i =0; i< nRows; i++){
 8             int n = i;
 9             while(n<len){
10                 sb.append(s.charAt(n));
11                 if(i!=0 && i!= nRows-1){
12                     n+=(nRows-i-1)<<1;
13                     if(n<len){
14                         sb.append(s.charAt(n));
15                         n+=i<<1;
16                     }
17                 }else{
18                     n+=(nRows-1)<<1;
19                 }
20             }
21         }
22         return sb.toString();
23     }

参考源码：https://github.com/pkufork/Martians/blob/master/src/main/java/com/pkufork/martians/leetcode/L6_ZigZagConversion.java