学步园

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".

难度系数:容易

实现

string convert(string s, int nRows) {
    if (nRows <= 1) {
        return s;
    }
    string *temps = new string[nRows];
    bool longmod = true;
    int row = 0;
    for (int i = 0; i < s.size(); ++i) {
        if (longmod) {
            temps[row].append(s.substr(i, 1));
            row++;
            if (row == nRows-1) {
                longmod = false;
            }
        } else {

            temps[row].append(s.substr(i, 1));
            row--;
            if (row == 0) {
                longmod = true;
            }
        }


    }
    string rets;
    for (int i = 0; i < nRows; ++i) {
        rets.append(temps[i]);
    }
    delete []temps;
    return rets;
}