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".

Zigzag:即循环对角结构.

向下循环:nRows

斜角线循环

重复...

#include <string>

#include <iostream>

using namespace std;

string convert(string s,int nRows){

     if(nRows==) return s;

         string res[nRows];

         int i==,j,gap=nRows-;

         while(i<s.size()){

               for(j=;j<nRows && i<s.size();j++) res[j]+=s[i++];

               for(j=gap;j> && i<s.size();j--) res[j]+=s[i++];

         }

         string ret="";

         for(i=;i<nRows;i++){

             ret+=res[i];

         }

         return ret;

}