6. ZigZag Conversion

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 String convert(String s, int numRows) {
        if(numRows==1)
        return s;
        char[][] chs = new char[numRows][s.length()];
		int row = 0, col = 0, status = 0;
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < s.length(); i++) {
			status = col % (numRows - 1);
			if (status == 0) {
				for (row = 0; row < numRows && i < s.length(); row++,i++){
					chs[row][col] = s.charAt(i);
				}
				i--;
				col++;
			} else {
				chs[numRows - status - 1][col] = s.charAt(i);
				col++;
			}
		}
		for(int i=0;i<numRows;i++)
			for(int j=0;j<s.length();j++)
				if(chs[i][j]!='\0')
				sb.append(chs[i][j]);
		return sb.toString();
    }
}