LeetCode 6. ZigZag Conversion 详细解析

这张图片是对ZigZag的描述和程序的核心思想
/************************************************************************
*
* 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”.
*
*
************************************************************************/

#include <iostream>#include <vector>#include <string>using namespace std;string convert(string s, int nRows) {    //The cases no need to do anything    if (nRows<=1 || nRows>=s.size()) return s;    vector<string> r(nRows);    int row = 0;    int step = 1;    for(int i=0; i<s.size(); i ++) {        if (row == nRows-1) step = -1;        if (row == 0) step = 1;        //cout << row <<endl;        r[row] += s[i];        row += step;    }    string result;    for (int i=0; i<nRows; i++){        result += r[i];    }    return result;}int main(int argc, char**argv){    string s;    int r;    s = "PAYPALISHIRING";    r = 5;    cout << s << " : " << convert(s, r) << endl;}