Fibonacci sequence
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: n = 2
Output: 1
Explanation: F(2) = F(1) + F(0) = 1 + 0 = 1.
Example 2:
Input: n = 3
Output: 2
Explanation: F(3) = F(2) + F(1) = 1 + 1 = 2.
Example 3:
Input: n = 4
Output: 3
Explanation: F(4) = F(3) + F(2) = 2 + 1 = 3.
Constraints:
0 <= n <= 30
1 Answer
class Solve
{
public static int sum()
{
Scanner in = new Scanner(System.in);
int a=0, b=1, c=0, d=0;
int n= in.nextInt();
for(int i=3; i<=n; i++)
{
c=a+b;
a=b;
b=c;
d=d+c;
}
return d;
}
}
class Fibonacci
{
public static void main(String[] args)
{
Solve s = new Solve();
System.out.println(s.sum());
}
}