leetcode[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".

class Solution {

public:

    string convert(string s, int nRows) 

{

    int n=s.length();

    if (n==0||n==1||nRows==1||n<=nRows)

    {

        return s;

    }

    string temp="";

    int k=(n-1)/(2*nRows-2);

    for (int i=0;i<nRows;i++)

    {

        if ((i==0)||(i==nRows-1))

        {

            temp+=s[i];

            for (int j=1;(j<=k)&&((i+j*(2*nRows-2))<n);j++)

            {

                temp+=s[i+j*(2*nRows-2)];

            }

        }

        else

        {

             temp+=s[i];

            int ntemp=i;

            int klast=(n-1-(nRows-1))/(2*nRows-2);

            int kk=(klast!=k)?(2*k):(2*k+1);

            for (int j=1;((j<=kk)&&(ntemp<n));j++)

            {

                if (j%2)

                {

                    ntemp+=(2*nRows-2*i-2);

                } 

                else

                {

                    ntemp+=2*i;

                }

                if (ntemp<n)

                {

                    temp+=s[ntemp];

                }

                else if(i>=nRows)

                {

                    return temp;

                }

            }

        }

    }

    return temp;

}

};