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Convert Date to Binary

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StringsBit Manipulation

You are given a string date representing a Gregorian calendar date in the yyyy-mm-dd format.

date can be written in its binary representation obtained by converting year, month, and day to their binary representations without any leading zeroes and writing them down in year-month-day format.

Return the binary representation of date.

Example 1:

Input: date = "2080-02-29"

Output: "100000100000-10-11101"

Explanation:

100000100000, 10, and 11101 are the binary representations of 2080, 02, and 29 respectively.

Example 2:

Input: date = "1900-01-01"

Output: "11101101100-1-1"

Explanation:

11101101100, 1, and 1 are the binary representations of 1900, 1, and 1 respectively.

Constraints:

date.length == 10
date[4] == date[7] == '-', and all other date[i]'s are digits.
The input is generated such that date represents a valid Gregorian calendar date between Jan 1^st, 1900 and Dec 31^st, 2100 (both inclusive).

Try coding it in LeetCode

Convert Date to Binary

Easy

Asked by:

8 views

Topics:

StringsBit Manipulation

You are given a string date representing a Gregorian calendar date in the yyyy-mm-dd format.

Return the binary representation of date.

Example 1:

Input: date = "2080-02-29"

Output: "100000100000-10-11101"

Explanation:

100000100000, 10, and 11101 are the binary representations of 2080, 02, and 29 respectively.

Example 2:

Input: date = "1900-01-01"

Output: "11101101100-1-1"

Explanation:

11101101100, 1, and 1 are the binary representations of 1900, 1, and 1 respectively.

Constraints:

date.length == 10
date[4] == date[7] == '-', and all other date[i]'s are digits.
The input is generated such that date represents a valid Gregorian calendar date between Jan 1^st, 1900 and Dec 31^st, 2100 (both inclusive).

Try coding it in LeetCode

Solution

Clarifying Questions

When you get asked this question in a real-life environment, it will often be ambiguous (especially at FAANG). Make sure to ask these questions in that case:

What is the expected date format for the input (e.g., YYYY-MM-DD, MM/DD/YYYY)?
What should be returned if the input date is invalid or outside a supported range?
Should the binary representation be a string of 0s and 1s, or some other data type like an array of booleans or integers?
How should the year, month, and day be represented in binary, and in what order should they be concatenated?
Is there a specific number of bits required for each part of the date (year, month, day) in the binary representation, or should the number of bits be determined by the value itself?

Brute Force Solution

Approach

The main idea is to individually convert the date's month, day, and year into their binary representations. Then, put these binary pieces together in the proper order to create the final binary date.

Here's how the algorithm would work step-by-step:

First, take the month part of the date and change it into its binary equivalent.
Next, do the same thing for the day part; convert it from the usual number to its binary form.
Then, convert the year part of the date into binary as well.
Finally, put the binary versions of the month, day, and year together to create the complete binary date.

Code Implementation

def convert_date_to_binary(month, day, year):
    # Convert the month to binary
    month_in_binary = bin(month)[2:]

    # Convert the day to binary
    day_in_binary = bin(day)[2:]

    # Convert the year to binary
    year_in_binary = bin(year)[2:]

    # Concatenate the binary strings
    binary_date = month_in_binary + day_in_binary + year_in_binary

    return binary_date

Big(O) Analysis

Time Complexity

O(log n) – The algorithm converts the month, day, and year to their binary representations. Converting a decimal number 'n' to binary involves repeatedly dividing by 2 until the quotient is 0. The number of divisions is proportional to the number of bits required to represent 'n' in binary, which is log2(n). Since each of the month, day, and year are converted independently, the overall time complexity is dominated by the largest of the three conversions, effectively making it O(log n), where 'n' refers to the largest possible value of month, day, or year.

Space Complexity

O(1) – The algorithm converts the month, day, and year individually into binary representations. These conversions are performed on separate variables that hold the binary results temporarily. The size of these variables is determined by the maximum possible values for month, day, and year, which are constant. Therefore, the algorithm uses a constant amount of extra space, regardless of the input date, and the space complexity is O(1).

Optimal Solution

Approach

The best way to convert a date to binary involves understanding how dates are structured and then breaking it down into its components. We'll isolate each part of the date and represent it in binary separately, then combine these binary parts.

Here's how the algorithm would work step-by-step:

First, get the year from the date.
Convert the year into its binary representation.
Next, get the month from the date (1 for January, 2 for February, and so on).
Convert the month into its binary representation.
Then, get the day of the month from the date.
Convert the day into its binary representation.
Finally, combine the binary representations of the year, month, and day into a single binary string. You might need to decide on a specific order to put these binary parts together (year first, then month, then day, for example).

Code Implementation

def convert_date_to_binary(year, month, day):
    year_binary = bin(year)[2:]

    # Convert month to binary.
    month_binary = bin(month)[2:]

    # Convert day to binary.
    day_binary = bin(day)[2:]

    # Concatenate the binary representations.
    combined_binary = year_binary + month_binary + day_binary

    return combined_binary

Big(O) Analysis

Time Complexity

O(1) – The algorithm extracts the year, month, and day from a given date. Converting each of these to binary involves a fixed number of operations, regardless of the input date. Specifically, the number of bits needed to represent the day and month are small constants. The year may require slightly more bits, but its length is also bounded. Therefore, the operations performed are constant and do not scale with input size, resulting in O(1) time complexity.

Space Complexity

O(1) – The algorithm converts the year, month, and day into their binary representations and concatenates them. The space used to store the binary representations of the year, month, and day is dependent on the maximum possible value for each component. Because the number of bits required to store these components are fixed regardless of the specific date provided, the extra space required for these binary strings is constant. No other auxiliary data structures that depend on the input date are created, so the overall space complexity is O(1).

Edge Cases

Case	How to Handle
Null or invalid date string input	Return an error or null if the date string is null, empty, or does not conform to a recognized date format.
Dates before the epoch (e.g., before January 1, 1970, for Unix timestamps)	Handle dates before the epoch correctly, potentially requiring special calculations or error handling depending on desired output.
Dates far in the future, potentially causing integer overflow when converting to timestamps	Use a data type capable of representing very large numbers (e.g., long) and check for potential overflow during timestamp calculation.
Leap year and leap second considerations	Ensure the date parsing and conversion logic correctly handles leap years and, if relevant, leap seconds according to the specified calendar system.
Ambiguous date formats (e.g., MM/DD/YYYY vs DD/MM/YYYY)	Require a specific, unambiguous date format to avoid misinterpretation and ensure consistent results.
Different time zones and daylight saving time	Specify and consistently use a single time zone, accounting for potential daylight saving time transitions if necessary.
Edge case date values, such as February 29th in a non-leap year or invalid month/day combinations	Perform thorough validation of the date components to reject invalid dates before attempting conversion.
Maximum date values representable by the target system (e.g., year 9999)	Determine the maximum representable date and handle dates exceeding this limit gracefully, such as by returning an error.

Null or invalid date string input

How to Handle:

Return an error or null if the date string is null, empty, or does not conform to a recognized date format.

Dates before the epoch (e.g., before January 1, 1970, for Unix timestamps)

How to Handle:

Handle dates before the epoch correctly, potentially requiring special calculations or error handling depending on desired output.

Dates far in the future, potentially causing integer overflow when converting to timestamps

How to Handle:

Use a data type capable of representing very large numbers (e.g., long) and check for potential overflow during timestamp calculation.

Leap year and leap second considerations

How to Handle:

Ensure the date parsing and conversion logic correctly handles leap years and, if relevant, leap seconds according to the specified calendar system.

Ambiguous date formats (e.g., MM/DD/YYYY vs DD/MM/YYYY)

How to Handle:

Require a specific, unambiguous date format to avoid misinterpretation and ensure consistent results.

Different time zones and daylight saving time

How to Handle:

Specify and consistently use a single time zone, accounting for potential daylight saving time transitions if necessary.

Edge case date values, such as February 29th in a non-leap year or invalid month/day combinations

How to Handle:

Perform thorough validation of the date components to reject invalid dates before attempting conversion.

Maximum date values representable by the target system (e.g., year 9999)

How to Handle:

Determine the maximum representable date and handle dates exceeding this limit gracefully, such as by returning an error.

Solution

Clarifying Questions

When you get asked this question in a real-life environment, it will often be ambiguous (especially at FAANG). Make sure to ask these questions in that case:

What is the expected date format for the input (e.g., YYYY-MM-DD, MM/DD/YYYY)?
What should be returned if the input date is invalid or outside a supported range?
Should the binary representation be a string of 0s and 1s, or some other data type like an array of booleans or integers?
How should the year, month, and day be represented in binary, and in what order should they be concatenated?
Is there a specific number of bits required for each part of the date (year, month, day) in the binary representation, or should the number of bits be determined by the value itself?

Brute Force Solution

Approach

The main idea is to individually convert the date's month, day, and year into their binary representations. Then, put these binary pieces together in the proper order to create the final binary date.

Here's how the algorithm would work step-by-step:

First, take the month part of the date and change it into its binary equivalent.
Next, do the same thing for the day part; convert it from the usual number to its binary form.
Then, convert the year part of the date into binary as well.
Finally, put the binary versions of the month, day, and year together to create the complete binary date.

Code Implementation

def convert_date_to_binary(month, day, year):
    # Convert the month to binary
    month_in_binary = bin(month)[2:]

    # Convert the day to binary
    day_in_binary = bin(day)[2:]

    # Convert the year to binary
    year_in_binary = bin(year)[2:]

    # Concatenate the binary strings
    binary_date = month_in_binary + day_in_binary + year_in_binary

    return binary_date

Big(O) Analysis

Time Complexity

Space Complexity

Optimal Solution

Approach

Here's how the algorithm would work step-by-step:

First, get the year from the date.
Convert the year into its binary representation.
Next, get the month from the date (1 for January, 2 for February, and so on).
Convert the month into its binary representation.
Then, get the day of the month from the date.
Convert the day into its binary representation.
Finally, combine the binary representations of the year, month, and day into a single binary string. You might need to decide on a specific order to put these binary parts together (year first, then month, then day, for example).

Code Implementation

def convert_date_to_binary(year, month, day):
    year_binary = bin(year)[2:]

    # Convert month to binary.
    month_binary = bin(month)[2:]

    # Convert day to binary.
    day_binary = bin(day)[2:]

    # Concatenate the binary representations.
    combined_binary = year_binary + month_binary + day_binary

    return combined_binary

Big(O) Analysis

Time Complexity

Space Complexity

Edge Cases

Case	How to Handle
Null or invalid date string input	Return an error or null if the date string is null, empty, or does not conform to a recognized date format.
Dates before the epoch (e.g., before January 1, 1970, for Unix timestamps)	Handle dates before the epoch correctly, potentially requiring special calculations or error handling depending on desired output.
Dates far in the future, potentially causing integer overflow when converting to timestamps	Use a data type capable of representing very large numbers (e.g., long) and check for potential overflow during timestamp calculation.
Leap year and leap second considerations	Ensure the date parsing and conversion logic correctly handles leap years and, if relevant, leap seconds according to the specified calendar system.
Ambiguous date formats (e.g., MM/DD/YYYY vs DD/MM/YYYY)	Require a specific, unambiguous date format to avoid misinterpretation and ensure consistent results.
Different time zones and daylight saving time	Specify and consistently use a single time zone, accounting for potential daylight saving time transitions if necessary.
Edge case date values, such as February 29th in a non-leap year or invalid month/day combinations	Perform thorough validation of the date components to reject invalid dates before attempting conversion.
Maximum date values representable by the target system (e.g., year 9999)	Determine the maximum representable date and handle dates exceeding this limit gracefully, such as by returning an error.

Null or invalid date string input

How to Handle:

Return an error or null if the date string is null, empty, or does not conform to a recognized date format.

Dates before the epoch (e.g., before January 1, 1970, for Unix timestamps)

How to Handle:

Handle dates before the epoch correctly, potentially requiring special calculations or error handling depending on desired output.

Dates far in the future, potentially causing integer overflow when converting to timestamps

How to Handle:

Use a data type capable of representing very large numbers (e.g., long) and check for potential overflow during timestamp calculation.

Leap year and leap second considerations

How to Handle:

Ensure the date parsing and conversion logic correctly handles leap years and, if relevant, leap seconds according to the specified calendar system.

Ambiguous date formats (e.g., MM/DD/YYYY vs DD/MM/YYYY)

How to Handle:

Require a specific, unambiguous date format to avoid misinterpretation and ensure consistent results.

Different time zones and daylight saving time

How to Handle:

Specify and consistently use a single time zone, accounting for potential daylight saving time transitions if necessary.

Edge case date values, such as February 29th in a non-leap year or invalid month/day combinations

How to Handle:

Perform thorough validation of the date components to reject invalid dates before attempting conversion.

Maximum date values representable by the target system (e.g., year 9999)

How to Handle:

Determine the maximum representable date and handle dates exceeding this limit gracefully, such as by returning an error.