You can try the following algorithm:

  1. pass through your input one digit per time
  2. use a hash to count how often each digit occurs
  3. once you are finished, pass through the hash (again) to see how many digits are ocuring two times
  4. print yes/no

Once you have done this, think how to adapt the algorithm to handle the special case 1111....

Have Fun! Rata

PS.: it is good that you looked for an old thread! However you'll get more answers if you'd opened a new thread and just had provided a link to the old one! well, next time ;-)

In reply to Re^2: Find duplicate digits by Ratazong
in thread Find duplicate digits by Anonymous Monk

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