LeetCode Online Judge 题目C# 练习 - 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".

 1         public static string ZigZagConversion(string s, int nRows)
 2         {
 3             if (nRows == 1)
 4                 return s;
 5 
 6             int currRow;
 7             bool goDown;
 8             string ret = "";
 9 
10             for (int r = 1; r <= nRows; r++)
11             {
12                 currRow = 1;
13                 goDown = true;
14                 for (int i = 0; i < s.Length; i++)
15                 {
16                     if (currRow == r)
17                         ret += s[i];
18 
19                     if (currRow != nRows && goDown)
20                         currRow++;
21                     else if (currRow == nRows)
22                     {
23                         currRow--;
24                         goDown = false;
25                     }
26                     else if (currRow != 1 && !goDown)
27                         currRow--;
28                     else if (currRow == 1)
29                     {
30                         currRow++;
31                         goDown = true;
32                     }
33                 }
34             }
35 
36             return ret;
37         }

代码分析：

　　分几行就撸几次，每次都从头到尾撸string s 一次。 一个currRow，每当currRow hit 当前的行r， ret += s[i]; 一个goDown flag 看着currRow该++还是--；

　　马勒隔壁，终于完了。