0420. Strong Password Checker

https://leetcode.com/problems/strong-password-checker

Description

A password is considered strong if the below conditions are all met:

• It has at least 6 characters and at most 20 characters.

• It contains at least one lowercase letter, at least one uppercase letter, and at least one digit.

• It does not contain three repeating characters in a row (i.e., "...aaa..." is weak, but "...aa...a..." is strong, assuming other conditions are met).

Given a string password, return the minimum number of steps required to make password strong. if password is already strong, return 0.

In one step, you can:

• Insert one character to password,

• Delete one character from password, or

• Replace one character of password with another character.

Example 1:

**Input:** password = "a"
**Output:** 5

Example 2:

**Input:** password = "aA1"
**Output:** 3

Example 3:

**Input:** password = "1337C0d3"
**Output:** 0

Constraints:

• 1 <= password.length <= 50

• password consists of letters, digits, dot '.' or exclamation mark '!'.

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