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".
模拟题，要特别注意k为1时的特殊情况处理。
1 class Solution { 2 public: 3 string convert(string s, int nRows) { 4 vector<string> v(nRows); 5 string ret; 6 bool down = true; 7 int n = s.size(); 8 int k = 0; 9 for (int i = 0; i < n; ++i) { 10 if (down) { 11 v[k].push_back(s[i]); 12 ++k; 13 if (k == nRows) { 14 k = max(0, nRows - 2); 15 if (k > 0) { 16 down = false; 17 } 18 } 19 } else { 20 v[k].push_back(s[i]); 21 --k; 22 if (k == 0) { 23 down = true; 24 } 25 } 26 } 27 for (int i = 0; i < nRows; ++i) { 28 int m = v[i].size(); 29 for (int j = 0; j < m; ++j) { 30 ret.push_back(v[i][j]); 31 } 32 } 33 return ret; 34 } 35 };
原文：http://www.cnblogs.com/dengeven/p/4009266.html