LeetCode-6 ZigZag Conversion

 1     public String convert(String s, int numRows) {
 2         int l=s.length();
 3         if(l<=numRows)
 4             return s;
 5         if(numRows==1)
 6             return s;
 7         int COL=numRows-1;//每块占的列数
 8         int numCols=(int)Math.ceil(l*1.0/(2*numRows-2))*COL;
 9         char[][] cs=new char[numRows][numCols];
10         int indexBlock=0,index=0;//块顺序，块中的编号
11         int r=0,c=0;//所在的行和列
12         //
13         //System.out.println("number of columns is "+numCols);
14         //
15         for(int i=0;i<numRows;i++)
16         {
17             for(int j=0;j<numCols;j++)
18             {
19                 cs[i][j]=0x7fff;
20             }
21         }
22         for(int i=0;i<l;i++)
23         {
24             indexBlock=(int)Math.floor(i*1.0/(2*numRows-2));
25             index=(int)(i%(2*numRows-2));
26             if(index<numRows)//竖列
27             {
28                 c=indexBlock*COL;
29                 r=index;
30                 cs[r][c]=s.charAt(i);
31                 //System.out.println("竖列  "+i+"th char "+s.charAt(i)+" row="+r+"  col="+c);
32             }
33             else //斜
34             {
35                 c=indexBlock*COL+index+1-numRows;
36                 r=numRows-(index-numRows)-2;
37                 cs[r][c]=s.charAt(i);
38                 //System.out.println("斜列  "+i+"th char "+s.charAt(i)+" row="+r+"  col="+c);
39             }
40         }
41         //输出
42         StringBuilder builder=new StringBuilder();
43         for(int i=0;i<numRows;i++)
44         {
45             for(int j=0;j<numCols;j++)
46             {
47                 if(cs[i][j]!=0x7fff)
48                 {
49                     builder.append(cs[i][j]);
50                 }
51             }
52         }
53         
54         return builder.toString();
55     }

 1    public String convert(String s, int numRows) {
 2         if(numRows==1) return s;
 3         if(s.length()<numRows) return s;
 4         String[] strs=new String[numRows];
 5         //initial
 6         for(int i=0;i<numRows;i++)
 7         {
 8             strs[i]="";
 9         }
10         int index=0,gap=numRows-2,rowIndex=0;
11         while(index<s.length())
12         {
13             for(rowIndex=0;rowIndex<numRows && index<s.length();rowIndex++) 
14             {
15                 strs[rowIndex]+=""+s.charAt(index++);
16             }
17             
18             for(rowIndex=gap;rowIndex<=gap && rowIndex>0 && index<s.length();rowIndex--)
19             {
20                 strs[rowIndex]+=""+s.charAt(index++);
21             }
22             
23         }
24         //输出
25         StringBuilder builder=new StringBuilder();
26         for(int i=0;i<numRows;i++)
27         {
28             builder.append(strs[i]);
29         }
30         return builder.toString();
31     }