算法练习6. ZigZag Conversion 把一串字符反N方向n行排列

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".

把一串字符反N方向n行排列：

class Solution {

public:

    string convert(string s, int numRows) {

        if (numRows <= 1)return s;

        string result;

        int i, j, k,len=s.length();

        int inter = numRows*2-2,step=0;

        for (i = 0; i < numRows; i++)

        {

            if (i!=0&&i !=numRows - 1)

            {

                step = inter - 2 * i;

                j = i;

                while (j < len)

                {

                    result += s.at(j);

                    j = j + step;

                    step = inter - step;

                }

            }

            else{

                step = inter;

                j = i;

                while (j < len)

                {

                    result += s.at(j);

                    j += step;

                }

            }

           

        }

        return result;

               

    }

};