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   NA P L S I I GY   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".

 

0				8				16
1			7	9			15	17
2		6		10		14		18
3	5			11	13			19
4				12				20

 

分两次循环，第一次是列，第二次是斜线。

java需使用stringbuffer才不会超时，使用string超时了。

1 public class Solution { 2     public String convert(String s, int nRows) { 3         if (nRows==1) { 4             return s; 5         } 6         7         StringBuffer[]    reBuffers=new StringBuffer[nRows]; 8         for (int i = 0; i < reBuffers.length; i++) { 9             reBuffers[i]=new StringBuffer();10         }11         int i=0,j=0,C=nRows-2;12         while (i
     
      0;j--) {20                 21                 reBuffers[j].append(s.charAt(i++));22                 23             }24             25         }26         27         StringBuffer    res=new StringBuffer();28         for (int k = 0; k < nRows; k++) {29             res.append(reBuffers[k]);30         }31         return res.toString();32     }33 }