[Coding] Number of People Aware of a Secret solution leetcode
On day
1, one person discovers a secret.
You are given an integer
delay, which means that each person will
share the secret with a new person
every day, starting from
delay days after discovering the secret. You are also given an integer
forget, which means that each person will
forget the secret
forget days after discovering it. A person
cannot share the secret on the same day they forgot it, or on any day afterwards.
Given an integer
n, return
the number of people who know the secret at the end of day n. Since the answer may be very large, return it
modulo 109 + 7.
Example 1:
[Coding] Number of People Aware of a Secret solution leetcode
Input: n = 6, delay = 2, forget = 4
Output: 5
Explanation:
Day 1: Suppose the first person is named A. (1 person)
Day 2: A is the only person who knows the secret. (1 person)
Day 3: A shares the secret with a new person, B. (2 people)
Day 4: A shares the secret with a new person, C. (3 people)
Day 5: A forgets the secret, and B shares the secret with a new person, D. (3 people)
Day 6: B shares the secret with E, and C shares the secret with F. (5 people)
Example 2:
Input: n = 4, delay = 1, forget = 3
Output: 6
Explanation:
Day 1: The first person is named A. (1 person)
Day 2: A shares the secret with B. (2 people)
Day 3: A and B share the secret with 2 new people, C and D. (4 people)
Day 4: A forgets the secret. B, C, and D share the secret with 3 new people. (6 people)
Constraints:
Number of People Aware of a Secret solution leetcode
2 <= n <= 10001 <= delay < forget <= n