0878.nth-magical-number

878. Nth Magical Number

题目

A positive integeris magicalif it is divisible by either Aor B.

Return the N-th magical number. Since the answer may be very large, return it modulo 10^9 + 7.

Example 1:

Input: N = 1, A = 2, B = 3
Output: 2

Example 2:

Input: N = 4, A = 2, B = 3
Output: 6

Example 3:

Input: N = 5, A = 2, B = 4
Output: 10

Example 4:

Input: N = 3, A = 6, B = 4
Output: 8

Note:

1. 1 <= N<= 10^9
2. 2 <= A<= 40000
3. 2 <= B<= 40000

解题思路

见程序注释