66. Plus One LeetCode Solution in Python

Plus One LeetCode Solution in Python 3.

Given a non empty array of decimal digits representing a non-begative integer.
Increment the integer, most significant digit is on the left. Each element contains a single digit.
No leading zeros except for the number 0.

Examples

• Input: digits = [1,2,3]
• Output: [1,2,4]
• Input array represents the int 123 + 1 = 124

• Input: digits = [9]
• Output: [1,0]
• Input array represents the int 9 + 1 = 10

• Input: digits = [9,9]
• Output: [1,0,0]
• Input array represents the int 99 + 1 = 100

Analysis

One solution is to convert the list elements into int.
Then add 1 and convert back to a list.

Test Code

import time
start_time = time.time()
def main():
    print("start")
    
    #digits = [1,2,3]
    digits = [9,9]
    print ("digits: " + str(digits))
    
    sol = Solution()
    result = sol.plusOne(digits)
    print("result is: "+ str(result))
    print("end")

class Solution:
    def plusOne(self, digits: list[int]) -> list[int]:

        tmp_int = 0
        for i in range(len(digits)):
            tmp_int += digits[i] * pow(10, (len(digits)-1-i))

        return list(map(lambda x: int(x), str(tmp_int+1)))

if __name__ == "__main__":
    main()
print("--- %s ms ---" % int(((time.time() - start_time)*1000)))

Test Output

start
digits: [9, 9]
result is: [1, 0, 0]
end
--- 31 ms ---
>>> 

Final Solution Code

    class Solution:
    def plusOne(self, digits: list[int]) -> list[int]:

        tmp_int = 0
        for i in range(len(digits)):
            tmp_int += digits[i] * pow(10, (len(digits)-1-i))

        return list(map(lambda x: int(x), str(tmp_int+1)))