How do you solve Count Days Spent Together on LeetCode?

Count Days Spent Together (LeetCode #2409) can be solved using Brute Force. The optimal approach is Brute Force with undefined time complexity and undefined space complexity. Key insight: We can check each day of the year to see if both Alice and Bob are in Rome on that day. This approach is straightforward but inefficient as it checks every day individually.

What is the time complexity of Count Days Spent Together?

The optimal solution for Count Days Spent Together runs in undefined time and uses undefined space. undefined

What algorithm or data structure is used to solve Count Days Spent Together?

Count Days Spent Together uses the following concepts: Math, String. The recommended patterns to study are: .

#2409

Count Days Spent Together

Easy

MathString

LeetCode ↗

Approaches

💡

Intuition

Time Space

We can check each day of the year to see if both Alice and Bob are in Rome on that day. This approach is straightforward but inefficient as it checks every day individually.

⚙️

Algorithm

3 steps

1Step 1: Convert the arrival and leave dates for Alice and Bob into a range of days (from 1 to 365).
2Step 2: Iterate through each day of the year and check if it falls within both Alice's and Bob's date ranges.
3Step 3: Count the total number of days that are common in both ranges.

solution.py22 lines

1# Full working Python code
2from datetime import datetime, timedelta
3
4def countDaysSpentTogether(arriveAlice, leaveAlice, arriveBob, leaveBob):
5    def date_to_day(date):
6        month, day = map(int, date.split('-'))
7        days_in_month = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
8        return sum(days_in_month[:month-1]) + day
9    
10    startAlice = date_to_day(arriveAlice)
11    endAlice = date_to_day(leaveAlice)
12    startBob = date_to_day(arriveBob)
13    endBob = date_to_day(leaveBob)
14    
15    count = 0
16    for day in range(1, 366):
17        if (startAlice <= day <= endAlice) and (startBob <= day <= endBob):
18            count += 1
19    return count
20
21# Example usage
22print(countDaysSpentTogether('08-15', '08-18', '08-16', '08-19'))

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