6. ZigZag Conversion

题目

 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". 

解析

// 6. ZigZag Conversion
class Solution_6 {
public:
    string convert(string s, int numRows) {
        if (numRows<=1)
        {
            return s;
        }
        //vector<string> vec; //numRows行 //
        //string vec[numRows]; bug

        string* vec = new string[numRows];
        int step = 0, row = 0;
        for (int i = 0; i < s.size();++i)
        {
            vec[row].push_back(s[i]);
            if (row == 0)
            {
                step = 1;
            }
            if (row == numRows-1)
            {
                step = -1;
            }
            row = row + step;
        }

        string str="";
        for (int i = 0; i < numRows; i++)
        {
            str += vec[i];
        }
        delete[] vec;

        return str;
    }
};

题目来源

• 6. ZigZag Conversion