问题：

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".

提示：

String

方法1：（效率中等）

char* convert(char* s, int numRows) {
    int len=strlen(s);
    int index;
    char *str=(char *)malloc((len+1)* sizeof(char));
    char *head=str;
    
    if(numRows==1){
        return s;
    }
    
    for(int row=0; row<numRows; row++){
        for(index=row; index<len; index+=2*numRows-2){
            *str++=s[index];
            if(row>0 && row<numRows-1 && (index+2*numRows-2-2*row)<len){
                *str++=s[index+2*numRows-2-2*row];
            }
        }
    }
    *str=‘\0‘;
    return head;
}

其他人用C语言写的：http://blog.csdn.net/u013300875/article/details/44121511

LeetCode 6 ZigZag Conversion (C)