leetcode中zigzag实现；

6. 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".

在这个地方，leetcode也只是举了一个例子，如果有对zigzag不熟悉的，可以自己去百度资料看一下，这里我想说的是，我们的每一行每两个字符间隔的宽度是和总共的字符的行数有关的，话不多说，还是直接贴代码

char* convert(char* s, int numRows) {
   int n=strlen(s);
   int i,j,step,k,temp;
   char *st;
   if(numRows<=1||n<numRows)
   return s;
   step=(numRows-1)*2;
   st=malloc(sizeof(char)*(n+1));
   st[n]='\0';
   for(i=k=0;i<numRows;i++){
       temp=(numRows-i-1)*2;
       for(j=i;j<n;j+=step){
           st[k++]=s[j]
            if( i > 0 && i < numRows - 1 && j + temp < n )
            st[k++] = s[j+temp];
       }
   }
}