Is Number of Days in a Month easy or hard?

Number of Days in a Month is classified as an Easy problem. The main challenge is remembering and correctly implementing the leap year rule while mapping months to their standard day counts.

Number of Days in a Month Python/Java solution

In Python or Java, define an array with month lengths and check if the month equals 2. If it is February, apply the leap year formula using modulo operations. Otherwise return the value directly from the array. The implementation remains O(1) time and space.

How to solve Number of Days in a Month in O(1)?

Use a precomputed array containing the number of days for each month. If the input month is February, evaluate the leap year condition: divisible by 4 but not by 100 unless also divisible by 400. Return 29 for leap years, otherwise 28.

What is the best approach for Number of Days in a Month?

The most common solution uses a fixed array for month lengths and a leap year check for February. You store the days for each month and adjust February to 29 if the year satisfies the leap year rule. This runs in O(1) time and O(1) space.

Is Number of Days in a Month asked at Google/Amazon/Meta?

The problem itself is more of a basic logic and calendar math question, typically seen in coding platforms like LeetCode for practice. Similar logic questions about date handling or leap year calculations can appear in interviews at large tech companies.

What data structure is used in Number of Days in a Month?

Most implementations use a simple array or list storing the days for each month. Aside from that, the solution mainly relies on arithmetic operations to evaluate the leap year rule.

What is the time complexity of Number of Days in a Month?

The optimal solution runs in O(1) time because it performs only a few arithmetic checks and a constant-time array lookup. Space complexity is also O(1) since only a small fixed array or a few variables are used.

Description Hints 2 Solution Video 4:01

1118. Number of Days in a Month

Easy59.4% acceptance1 companyPremium elsewhere, free here

Given a year year and a month month, return the number of days of that month.

Example 1:

Input: year = 1992, month = 7
Output: 31

Example 2:

Input: year = 2000, month = 2
Output: 29

Example 3:

Input: year = 1900, month = 2
Output: 28

Constraints:

1583 <= year <= 2100
1 <= month <= 12

Asked at 1 company

Amazon

Topics

Math

Hints open one at a time

Hint 1

Does February have 28 days or 29 days?

Hint 2

Think of Leap years.

4:01

Still stuck?Read the written solution, or watch a walkthrough.

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1class Solution:
  def solve(self):
      pass


Starter codePython 3Spaces: 4

Examples

Case 1Case 2Case 3

Input

1992
7

Input

2000
2

Input

1900
2

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