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Fibonacci Number - Array - Easy - LeetCode - MiniTV

Fibonacci Number - Array - Easy - LeetCode - मिनी टीवी

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.

public class Solution {
    public int Fib(int N) {        
        
        int f1 = 0;
        int f2 = 1;
        int sum = 1;
        
        if(N==0){
            return f1;
        }
        
        for(int i=2;i<=N;i++){
            sum=f1+f2;
            f1=f2;
            f2=sum;            
        }
        
        return sum;
    }
}

Time Complexity: O(n)

Space Complexity: O(1)