Harden the Password

Hard

A security policy treats a password as strong when all of these hold: - it is between 6 and 20 characters long, inclusive; - it has at least one lowercase English letter, at least one uppercase letter and at least one digit; - it never has three equal characters in a row (xAaaa1 is not allowed, xAaxa1 is fine). One edit inserts a character, deletes a character or replaces one character with another. Given the string password, return the smallest number of edits that makes it strong. If it is strong already, return 0.

Example 1

password='ab' → 4

The password is 4 characters short of six, and it also lacks an uppercase letter and a digit. Four insertions fix everything at once, for example abC12x.

Example 2

password='Qwerty1111' → 1

Length and character kinds are fine, but four 1s in a row break the rule. Replacing one of them is enough: Qwerty11x1.

Example 3

password='Spring.Day.2026' → 0

The password is already strong.

Constraints

1 ≤ password.length ≤ 100
password consists of printable ASCII characters other than space (codes 33 to 126)

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Topics

Greedy String Heap (Priority Queue)

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Equal Letters Kept Apart Hard No Twin Letters Side by Side Medium Three Letters, No Triples Medium Largest String With a Run Cap Medium Fill the Blanks With the Fewest Repeats Medium

Input

password='ab'

Expected

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