- Difficulty: Hard
- Tags: LeetCode, Hard, Greedy, String, Heap (Priority Queue), leetcode-420, O(n), O(1)
Problem
A password is considered strong if the below conditions are all met:
- It has at least
6
characters and at most20
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.,
"Baaabb0"
is weak, but"Baaba0"
is strong).
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'!'
.