Is Date Range Generator easy or hard?

Date Range Generator is typically considered a medium-level problem. The logic is simple iteration, but candidates must understand JavaScript generators, date manipulation with the Date API, and how to produce values lazily.

Date Range Generator Python/Java solution

In Python, a similar approach can be implemented using a generator with yield and the datetime.timedelta class. In Java, the range can be produced using LocalDate and incremented with plusDays(step) inside a loop or stream.

How to solve Date Range Generator in O(n)?

Initialize a Date object with the start date and loop until it exceeds the end date. On each iteration yield the current date and increment it using setDate(current.getDate() + step). This processes each date exactly once, resulting in O(n) time.

What is the best approach for Date Range Generator?

The generator-based iteration approach is the best solution. It iterates from the start date to the end date while yielding each date lazily. This keeps time complexity at O(n) while maintaining O(1) space since only the current date object is stored.

Is Date Range Generator asked at Google/Amazon/Meta?

Problems involving date manipulation and generator patterns appear in frontend and JavaScript-focused interviews. Variations of range generators and lazy iteration are common in companies evaluating JavaScript fundamentals and API design skills.

What data structure is used in Date Range Generator?

The optimal solution relies on a generator function combined with the built-in Date object. The generator controls iteration flow while the Date object handles date arithmetic and comparisons.

What is the time complexity of Date Range Generator?

The time complexity is O(n), where n is the number of generated dates between the start and end range. Each iteration performs constant work: checking the date boundary, yielding the value, and incrementing the date by the step.

2777. Date Range Generator - Practice Online

Given a start date start, an end date end, and a positive integer step, return a generator object that yields dates in the range from start to end inclusive.

The value of step indicates the number of days between consecutive yielded values.

All yielded dates must be in the string format YYYY-MM-DD.

Example 1:

Input: start = "2023-04-01", end = "2023-04-04", step = 1
Output: ["2023-04-01","2023-04-02","2023-04-03","2023-04-04"]
Explanation: 
const g = dateRangeGenerator(start, end, step);
g.next().value // '2023-04-01'
g.next().value // '2023-04-02'
g.next().value // '2023-04-03'
g.next().value // '2023-04-04'

Example 2:

Input: start = "2023-04-10", end = "2023-04-20", step = 3
Output: ["2023-04-10","2023-04-13","2023-04-16","2023-04-19"]
Explanation: 
const g = dateRangeGenerator(start, end, step);
g.next().value // '2023-04-10'
g.next().value // '2023-04-13'
g.next().value // '2023-04-16'
g.next().value // '2023-04-19'

Example 3:

Input: start = "2023-04-10", end = "2023-04-10", step = 1
Output: ["2023-04-10"]
Explanation: 
const g = dateRangeGenerator(start, end, step);
g.next().value // '2023-04-10'

Constraints:

new Date(start) <= new Date(end)
start and end dates are in the string format YYYY-MM-DD
0 <= The difference in days between the start date and the end date <= 1500
1 <= step <= 1000