Column name from a given column number Excel

Column name from a given column number Excel

  April 30, 2018    

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Idea is to find remainder with 26.
if it is 0 it means we are going to use Z else add A+rem-1 (-1 because A =1)
divide n by 26 , if remainder is 0 then also decrement n as we have already used 26 fully by Z ,

if 26/26=1 but we don't need it


import java.util.*;
import java.lang.*;
import java.io.*;
class colmExcel
 {
   public static void colmn(long n)
   {
     String str=new String();
     long res=-1;
     while(n>0)
      {
        res=n%26;
        if(res!=0)
        {
          str+=(char)('A'+(res-1));
          //System.out.println((char)('A'+(res-1)));
        }
        else
        {
          str+=(char)('Z');
        }
        n/=26;
        if(res==0)
        --n;
      }
      for(int i=str.length()-1;i>=0;--i)
      System.out.print(str.charAt(i));
      //return str;
   }
public static void main (String[] args)
{
Scanner ab=new Scanner(System.in);
int t=ab.nextInt();
while(t-->0)
{
    long n=ab.nextLong();
      colmn(n);
    System.out.println();
}
}
}