题目描述
Particle swarm optimization ( PSO ) is a population-based stochastic optimization algorithm.
In addition to the basic structure of PSO, there is also a variant called star-topology PSO,
which introduces a star-shaped communication structure among particles. In this structure,
there is a central particle called the leader, which is responsible for gathering and disseminating
information to the rest of the particles in the swarm.
Now there are n particles on the star-topology. Among the n particles, there is one particle
as the leader, and there is an edge between the other particles and the leader. For a piece of
information, it can be propagated along an edge on the topology.
To examine the benefits of this topology, we need to calculate the following data:
We define that X is number of edges required for them to exchange information for two different
particles. Please calculate the expected value rounded off and maximum value of X.
输入
输出
样例输入 Copy
2
4
7
样例输出 Copy
1.500000000 2.000000000
1.714285714 2.000000000