Watch 10 video solutions for Minimum Additions to Make Valid String, a medium level problem involving String, Dynamic Programming, Stack. This walkthrough by Nick White has 34,033 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
Given a string word to which you can insert letters "a", "b" or "c" anywhere and any number of times, return the minimum number of letters that must be inserted so that word becomes valid.
A string is called valid if it can be formed by concatenating the string "abc" several times.
Example 1:
Input: word = "b" Output: 2 Explanation: Insert the letter "a" right before "b", and the letter "c" right next to "b" to obtain the valid string "abc".
Example 2:
Input: word = "aaa" Output: 6 Explanation: Insert letters "b" and "c" next to each "a" to obtain the valid string "abcabcabc".
Example 3:
Input: word = "abc" Output: 0 Explanation: word is already valid. No modifications are needed.
Constraints:
1 <= word.length <= 50word consists of letters "a", "b" and "c" only.