LeetCode Python Solutions: 66. Plus One #python #coding #leetcode

ZeroStress LeetCode Python Solutions: 66. Plus One #python #leetcode

The intuition behind the solution is to treat the digits in the input list as a single integer, increment that integer by one, and then convert it back to a list of digits.

The approach taken in the solution is as follows:

Convert each digit in the input list digits to a string using a list comprehension. This step is done to facilitate concatenation of the digits later.

Join the string representation of the digits to form a single string using the join() method. This creates a string representing the original integer.

Convert the string back to an integer by using the int() function. Now, we have the original integer representation of the digits.

Add 1 to the integer to perform the increment operation.

Convert the incremented integer back to a string using the str() function.

Create a list numStrList by splitting the string into individual characters.
This gives us a list of characters representing the incremented digits.

Convert each character in numStrList back to an integer using a list comprehension to obtain the final list of digits numList.

Return numList as the result.

The overall logic is to convert the input list of digits to an integer, increment it by one, and then convert the incremented integer back to a list of digits. This approach allows us to perform the increment operation as if we were operating on a regular integer, leveraging the convenience of Python's string and integer conversion functions.

Let's break down the code for the problem '66. Plus One' and understand its logic, syntax, and mechanism.

The Solution class is defined, which will contain the method plusOne to solve the problem.

The plusOne method takes a list of integers digits as input and returns a list of integers as output.

a = [str(i) for i in digits] creates a new list a by converting each integer element of digits into a string using a list comprehension.

a = int(''.join(a)) converts the list a into a single string by joining all the string elements together. Then, it converts the resulting string into an integer using the int function. This represents the original number stored in the digits list.

b = a + 1 increments the number a by 1, as per the problem's requirement.

numStrList = list(str(b)) converts the incremented number b into a string and creates a list numStrList with each digit of the string as an element.

numList = [int(x) for x in numStrList] converts each element of the numStrList from string to integer using a list comprehension. This creates the final list numList, which represents the incremented number as separate digits.

Finally, numList is returned as the output.

Now let's talk about the logic and algorithm behind the code:

The given list digits represents a large integer, where each element corresponds to a digit in the number, with the most significant digit at the beginning of the list.
To increment the number by 1, the approach is to convert the list to a string representation, then convert it back to an integer, increment the integer by 1, and convert it back to a list of digits.

Time Complexity:

The time complexity of the solution is primarily determined by the operations of converting the list to a string (O(n), where n is the length of the list) and converting the string back to a list (O(n)).

The overall time complexity can be considered as O(n), where n is the length of the input list.

Space Complexity:

The space complexity is determined by the additional lists created: a, numStrList, and numList.

The space complexity can be considered as O(n), where n is the length of the input list.

While this solution provides a straightforward approach to solve the problem, it is important to note that it involves multiple conversions between lists, strings, and integers, which may not be the most efficient solution. There are alternative approaches that can solve the problem more optimally.
00:00 Code
02:45 Main
10:50 End

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- Time complexity: O(n + m)

The time complexity of the given solution can be analyzed as follows:

Converting the digits to a string representation takes O(n) time, where n is the length of the input list digits.

Joining the strings and converting the resulting string to an integer also takes O(n) time.

Incrementing the integer by 1 is a constant time operation.

Converting the incremented integer back to a list of digits takes O(m) time, where m is the number of digits in the incremented integer.
Overall, the time complexity of the solution is O(n + m), where n is the length of the input list and m is the number of digits in the incremented integer.

- Space complexity:O(1)

The space complexity of the solution is O(1) since we are performing the operation in-place, modifying the input list digits without using any additional data structures that scale with the input size. Therefore, the space complexity is constant and does not depend on the input size.

[NeedCodeLeetCode]

The intuition behind solving this problem using the given code is as follows:

Convert the list of digits into a string representation: The code begins by converting each digit in the input list digits into a string and creating a new list a with these string elements. This step allows us to represent the number stored in digits as a single string.

Convert the string representation into an integer: The next step is to join the string elements in a to form a single string representing the number. This string is then converted into an integer using the int function and stored in the variable a.

Increment the integer representation by 1: The integer a is incremented by 1 to reflect the requirement of adding 1 to the original number.

Convert the incremented integer back to a list of digits: The incremented integer a is converted back into a string using str, and then each character of the string (representing a digit) is extracted and stored in the list numStrList.

Convert the string digits to integers and return the result: Each element in numStrList is converted back to an integer using a list comprehension, resulting in the final list numList. This list represents the incremented number as separate digits.

Return the final result: The numList is returned as the solution to the problem.

The overall intuition is to convert the list of digits into an integer representation, increment the integer, and then convert it back to a list of digits. This approach allows us to perform the required addition and obtain the desired result.