ZigZag Conversion

https://leetcode.com/problems/zigzag-conversion/

题目理解:http://blog.csdn.net/ljiabin/article/details/40477429

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".

public class Solution {
    public static String convert(String s, int numRows) {
    if(numRows==1) return s;
        String[]re=new String[numRows];
        for(int i=0;i<numRows;i++){re[i]="";}
        int len=s.length();
        for(int i=0;i<len;i++){
            char c=s.charAt(i);
            int row=i%(2*numRows-2);
            if(row>=numRows) row=2*numRows-row-2;
            re[row]+=c;
        }
        String answer="";
        for(int i=0;i<numRows;i++){
            answer+=re[i];
        }
        return answer;
    }
    public static void main(String[]args){
    System.out.println(convert("PAYPALISHIRING", 3));
    }
}