Discover the quantity N, the place (N+X) divisible by Y and (N-Y) divisible by X

Given two numbers X and Y. the duty is to seek out the quantity N (N ≤ 10^18) which satisfies these two circumstances:

• (N + X) is divisible by Y
• (N – Y) is divisible by X

Examples:

Enter: X = 18, Y = 42
Output:780

Enter: X = 100, Y = 200
Output: 500

Strategy: The issue may be solved primarily based on the next concept:

We are able to implement the easy math idea of the quantity system.

• N + X = Y    …………(i)
• N – Y = X     …………(ii)

Normalizes the equation we will get N could also be equal to (X*Y – X + Y). Additionally, it’s satisfying these two circumstances. So, the reply is (X * Y – X + Y).

Beneath is the implementation of the above strategy:

Time Complexity: O(1)
Auxiliary Area: O(1)