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My Thoughts
What Went Well
I knew how to approach the problem optimally, and I had fun while doing so because I got to combine a lot of different data structures and operations.
Comments We could optimize the code further by checking the first element outside of the for loop, so then we would only need to check if c2 meets the criteria, but this would add a lot of confusion and lines to the program. Furthermore, since the password’s maximum length is only 100 characters, the potential speedup for this improvement will not be seen.
Data Structure Description
Hash Map (Dictionary) - A data structure that stores a collection of keys, each to their respective values. Each key may only appear once.
Hash Table (Set) - An unordered container of non-repeating values.
Visual Examples
An array being transformed into a set, click to view
Solution Statistics
Time Spent Coding
6 minutes
Time Complexity
O(n) - Each character in the password must be seen at least once, resulting in the O(n) time complexity.
Space Complexity
O(1) - The number of variables created is independent of the length of the password, resulting in the O(1) space complexity.
Runtime Beats
96.50% of other submissions
Memory Beats
68.42% of other sumbissions
Solution
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class Solution(object):
def strongPasswordCheckerII(self, password):
if len(password) < 8: return False
criteria = { "lower" : False,
"upper" : False,
"digit" : False,
"Special" : False
}
specials = set(["!","@","#","$","%","^","&","*","(",")","-","+"])
for i,c1 in enumerate(password[:len(password)-1]):
c2 = password[i+1]
# If character1 (c1) is equal to c2 (its adjacent character)
# return False, this password is invalid (not strong)
if c1 == c2: return False
if c1.isupper() or c2.isupper():
criteria["upper"] = True
if c1.islower() or c2.islower():
criteria["lower"] = True
if c1.isdigit() or c2.isdigit():
criteria["digit"] = True
if c1 in specials or c2 in specials:
criteria["special"] = True
# If the criteria dictionary contains false as one of its values
# then the password did not meet all criteria, return False
return False not in criteria.values()