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

Write the code that will take a string and make this conversion given a number of rows:

string convert(string text, int nRows);

class Solution {
    public String convert(String s, int numRows) {
        char c[] = s.toCharArray();
        int len = c.length;
        StringBuffer sb[] = new StringBuffer[numRows];
        for(int i = 0; i < sb.length; i++)
            sb[i] = new StringBuffer();

        int i = 0;
        while(i < len) {
            for(int j = 0; j < numRows && i < len; i++, j++) {
                sb[j].append(c[i]);
            }
            for(int j = numRows - 2; j > 0 && i < len; i++, j--) {
                sb[j].append(c[i]);
            }
        }

        for(int j = 1; j < sb.length; j++) {
            sb[0].append(sb[j]);
        }
        return sb[0].toString();
    }
}