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;   //行数为1，则字符串不变
int x = 2 * (numRows-1);   // 对数据进行分组 |/|/|...（|/）
int len = s.length();
char[] c = new char[len];  //两个字符串的长度是一样的
int k =0;
for(int i=0; i < numRows; i++)
{
for(int j=i;j<len;j=j+x)
{
c[k++] = s.charAt(j);    //根据规则一行一行输入数据（|）
if(i>0 && i<numRows-1 && j+x-2*i < len)    //判断是否符合（/）则按另一种规则放置字符
{
c[k++] = s.charAt(j+x-2*i);
}
}
}
return new String(c);
}
}