Help Needed in CSES Shortest Subsequence Problem
Difference between en1 and en2, changed 2 character(s)
Can anyone suggest me how to solve this problem(https://cses.fi/problemset/task/1087)↵

You are given a DNA sequence consisting of characters A, C, G, and T.↵

Your task is to find the shortest DNA sequence that is not a subsequence of the original sequence.↵

Input↵

The only input line contains a DNA sequence with n characters.↵

Output↵

Print the shortest DNA sequence that is not a subsequence of the original sequence. If there are several solutions, you may print any of them.↵

Constraints↵
1≤n≤106↵
Example↵

Input:↵
ACGTACGT↵

Output:↵
AAA

History

 
 
 
 
Revisions
 
 
  Rev. Lang. By When Δ Comment
en3 English SEH_LENGE_THODA 2020-11-13 15:18:27 2 Tiny change: 'nts\n1≤n≤106\nExample' -> 'nts\n1≤n≤1e6\nExample'
en2 English SEH_LENGE_THODA 2020-11-13 15:18:03 2 Tiny change: 'sk/1087)\nYou are ' -> 'sk/1087)\n\nYou are '
en1 English SEH_LENGE_THODA 2020-11-13 15:17:36 606 Initial revision (published)