LeetCode Python [updating]

Introduction

――Since I use Ruby at work, I mainly solved competitive programming with Ruby, but at the next workplace, I will practice Python little by little every day because I will use Python, and I will leave it in Qiita as a memorandum. The subject is Let Code. --I'm not familiar with Python, so feel free to comment.

Easy 1108.Defanging an IP Address --Summary: Replace. With [.]

• Input: "1.1.1.1"
• Expected: "1[.]1[.]1[.]1" --Replace: ** replace **

class Solution:
    def defangIPaddr(self, address: str) -> str:
        return address.replace(".","[.]") 

771.Jewels and Stones --Summary: Count how many letters J are in S

• Input: J = "aA", S = "aAAbbbb"
• Output: 3 --Answer 1: Use strings like arrays --Arrange strings: ** list ** --Character count: ** count **

class Solution:
    def numJewelsInStones(self, J: str, S: str) -> int:
        cnt = 0
        chars = list(J)
        for e in chars:
            cnt += S.count(e)
        return cnt

--Answer 2: Use strings like arrays --I didn't know that strings can be treated like arrays as they are --for x in string:

class Solution:
    def numJewelsInStones(self, J: str, S: str) -> int:
        cnt = 0
        for e in J:
            cnt += S.count(e)
        return cnt

--Answer 3: Use anonymous function ――I think Python's lambda is a map in Ruby. --The shape is special and processing for arrays (map (lambda variable: processing for variables, arguments))

class Solution:
    def numJewelsInStones(self, J: str, S: str) -> int:
        return sum(map(lambda x:S.count(x),J))

1281.Subtract the Product and Sum of Digits of an Integer --Summary: Number of all digits multiplied by --- Number of all digits added

• Input: n = 234
• Output: 15 --Answer 1: Calculate as an array with lambda --Create a number array with the lambda you just remembered. With Ruby, you can immediately imagine with map and to_i --String => Integer: ** int ** --Integer => string: ** str **

class Solution:
    def subtractProductAndSum(self, n: int) -> int:
        ary = list(map(lambda x: int(x), list(str(n))))
        n = 1
        m = 0
        for i in ary:
            n *= i
        for j in ary:
            m += j
        ans = n - m
        return ans

--Answer 2: Calculate as a string array (Sophisticated form of Answer 1) --Use **; ** for multiple tasks --Use **: ** in block units?

class Solution:
    def subtractProductAndSum(self, n: int) -> int:
        a, b = 0, 1
        for i in str(n): a += int(i); b *= int(i)
        return b - a

1221.Split a String in Balanced Strings

--Summary: How many pairs of R and L can be created under the condition that R and L must have the same number of characters?

• Input: s = "RLRRLLRLRL"
• Output: 4 --Answer 1: Count the number of pairs by setting 1 if R appears and -1 if L appears.

class Solution:
    def balancedStringSplit(self, s: str) -> int:
        r = 0
        output = 0
        for e in s:
            if e == 'R':
                r += 1
            if e == 'L':
                r -= 1
            
            if r == 0:
                output += 1
        return output