Problem statement

https://binarysearch.com/problems/Line-of-People/

Solution

We have equations x <= b and x <= n - 1 - a, from here we can get answer that x can be in [0, min(b, n - 1 - a)] and we have min(b, n - 1 - a) + 1 options.

Complexity

It is O(1) for time and space.

Code

class Solution:
    def solve(self, n, a, b):
        return min(b, n - 1 - a) + 1