Force buckle 989 Integer addition in array form

989. The addition of integers in the form of arrays

The integer Array form num Is an array of numbers in left to right order .

 for example , about  num = 1321 , The array form is  [1,3,2,1] .

Given num , The integer Array form , And integer k , return Integers num + k Of Array form .

Knowledge points involved

String conversion

class Solution:
    def addToArrayForm(self, A: List[int], K: int) -> List[int]:
        K = list(map(int,str(K)))
        res = []
        i,j = len(A)-1,len(K)-1
        carry = 0

        while i >= 0 and j >= 0:
            res.append(A[i] + K[j] + carry)
            res[-1],carry = res[-1] % 10, res[-1] // 10
            i -= 1
            j -= 1
        while i >= 0:
            res.append(A[i] + carry)
            res[-1],carry = res[-1] % 10, res[-1] // 10
            i -= 1
        while j >= 0:
            res.append(K[j] + carry)
            res[-1],carry = res[-1] % 10, res[-1] // 10
            j -= 1

        if carry:
            res.append(1)

        return res[::-1]

map() function

in other words ,map You can map the array of this question

del square(x):
    return x ** 2
 
map(square,[1,2,3,4])#[1,4,9,16] 
map(int,'1234')      #[1,2,3,4]

class Solution:
    def addToArrayForm(self, num: List[int], k: int) -> List[int]:
        return [int(i) for i in str((int(str(num)[1:-1:3]))+k)]
or:
        return list(map(int,str(int(''.join(str(num))) + K)))