LeetCode 168

Excel Sheet Column Title

Given a positive integer,
return its corresponding column title as appear in an Excel sheet.

For example:

1 -> A
2 -> B
3 -> C
...
26 -> Z
27 -> AA
28 -> AB

/*************************************************************************
    > File Name: LeetCode168.c
    > Author: Juntaran
    > Mail: JuntaranMail@gmail.com
    > Created Time: Tue 10 May 2016 08:06:44 PM CST
 ************************************************************************/

/*************************************************************************
    
    Excel Sheet Column Title
    
    Given a positive integer, 
    return its corresponding column title as appear in an Excel sheet.

    For example:

        1 -> A
        2 -> B
        3 -> C
        ...
        26 -> Z
        27 -> AA
        28 -> AB 
        
 ************************************************************************/
 
#include <stdio.h>

char* convertToTitle( int n )
{
    if( n < 1 )
    {
        return "";
    }
    int i;
    int count = 0;
    for( i=n-1; i>=0; i=i/26-1 )
    {
        count ++;
    }
    char* ret = (char*)malloc(sizeof(char)*count);
    for( i=n-1; i>=0; i=i/26-1 )
    {
        ret[--count] = i%26 + 'A';
    }
    return ret;
}

int main()
{
    int n = 28;
    char* ret = convertToTitle(n);
    printf("%s
", ret);
}