ZigZag Conversion 题解

题目来源：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".

解题思路：

对勾的形式一个周期～hash一下到具体哪一个row～

0            0            0
1        5    1        5
2    4        2    4
3            3

string convert(string s, int nRows)
{
   if(nRows == 1) return s;
   vector<vector<char> > rows(nRows);
   int T = nRows + nRows - 2;
   for(int i = 0; i < s.length(); i++)
   {
       int bucket = i % T;
       bucket = bucket >= nRows ? (T - bucket) : bucket;
       rows[bucket].push_back(s[i]);
   }
   string result="";
   for(int i = 0; i < nRows; i++)
   {
       for(int j = 0; j < rows[i].size(); j++)
           result += rows[i][j];
   }
   return result;
}