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".
思路：之字形转换如下：
观察可以发现：竖着的每一列都有numRows个元素，斜着的有numRows-2个元素，于是我们可以把竖着的一列和斜着的一列看成是一个循环周期，按照从上到下在从左下角到右上角的顺序存储字符。设置一个string数组，行数为numRows。
class Solution { public: string convert(string s, int numRows) { if (s.empty()) return ""; if (s.size() == 1) return s; string *ss = new string[numRows]; int i = 0, gap = numRows - 2; while (i < s.size()) { for (int j = 0; j < numRows&&i < s.size();++j) ss[j] += s[i++]; for (int j = gap;j > 0 && i < s.size();--j) ss[j] += s[i++]; } string str; for (int i = 0; i < numRows;i++) str += ss[i]; delete[] ss; ss = NULL; return str; } };
