fib.go

/* https://leetcode.com/problems/fibonacci-number/
The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence,
such that each number is the sum of the two preceding ones, starting from 0 and 1. That is,

F(0) = 0,   F(1) = 1
F(N) = F(N - 1) + F(N - 2), for N > 1.
Given N, calculate F(N).

Example 1:

	Input: 2
	Output: 1
	Explanation: F(2) = F(1) + F(0) = 1 + 0 = 1.

Example 2:

	Input: 3
	Output: 2
	Explanation: F(3) = F(2) + F(1) = 1 + 1 = 2.

Example 3:

	Input: 4
	Output: 3
	Explanation: F(4) = F(3) + F(2) = 2 + 1 = 3.
Note:

0 ≤ N ≤ 30.
*/

package larray

func fib(N int) int {
	switch N {
	case 0:
		return 0
	case 1:
		return 1
	default:
		a, b := 0, 1
		for i := 2; i <= N; i++ {
			a, b = b, a+b
		}
		return b
	}
}