{leetcode}/problems/minimum-deletions-to-make-string-balanced/[LeetCode - 1653. Minimum Deletions to Make String Balanced ^]
You are given a string s consisting only of characters 'a' and 'b'.
You can delete any number of characters in s to make s balanced. s is balanced if there is no pair of indices (i,j) such that i < j and s[i] = 'b' and s[j]= 'a'.
Return the minimum number of deletions needed to make _`s` *balanced*_.
Example 1:
Input: s = "aababbab"
Output: 2
Explanation: You can either:
Delete the characters at 0-indexed positions 2 and 6 ("aa[.underline]#b#abb[.underline]#a#b" -> "aaabbb"), or
Delete the characters at 0-indexed positions 3 and 6 ("aab[.underline]#a#bb[.underline]#a#b" -> "aabbbb").
Example 2:
Input: s = "bbaaaaabb" Output: 2 Explanation: The only solution is to delete the first two characters.
Constraints:
-
1 ⇐ s.length ⇐ 105 -
s[i]is'a'or'b'.