Given n strings, concatenate them in an order that produces the lexicographically smallest possible string.
Input : a = ["c", "cb", "cba"] Output : cbacbc Possible strings are ccbcba, ccbacb, cbccba, cbcbac, cbacbc and cbaccb. Among all these strings, cbacbc is the lexicographically smallest. Input : a = ["aa", "ab", "aaa"] Output : aaaaaab
One might think that sorting the given strings in the lexicographical order and then concatenating them produces the correct output. This approach produces the correct output for inputs like [“a”, “ab”, “abc”]. However, applying this method on [“c”, “cb”, “cba”] produces the wrong input and hence this approach is incorrect.
The correct approach is to use a regular sorting algorithm. When two strings a and b are compared to decide if they have to be swapped or not, do not check if a is lexicographically smaller than b or not. Instead check if appending b at the end of a produces a lexicographically smaller string or appending a at the end of b does. This approach works because we want the concatenated string to be lexicographically small, not the individual strings to be in the lexicographical order.
Time complexity : The above code runs inO(M * N * logN) where N is number of strings and M is maximum length of a string.
- Lexicographically smallest string formed by appending a character from the first K characters of a given string
- Lexicographically smallest string formed by appending a character from first K characters of a string | Set 2
- Lexicographically smallest string whose hamming distance from given string is exactly K
- Lexicographically smallest string of length N and sum K
- K-th lexicographically smallest unique substring of a given string
- Lexicographically smallest permutation of a string with given subsequences
- Queries to answer the X-th smallest sub-string lexicographically
- Find the lexicographically smallest string which satisfies the given condition
- Swap all occurrences of two characters to get lexicographically smallest string
- Lexicographically smallest string formed by removing at most one character
- Generate lexicographically smallest string of 0, 1 and 2 with adjacent swaps allowed
- Form lexicographically smallest string with minimum replacements having equal number of 0s, 1s and 2s
- Lexicographically smallest array after at-most K consecutive swaps
- Print the lexicographically smallest array by swapping elements whose sum is odd
- Find the lexicographically smallest sequence which can be formed by re-arranging elements of second array
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.