Create Fibonacci_Number.py

Author: SHREYASH96OG

Fibonacci_Number.py

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+# 509. 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: 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
+
+# solution
+class Solution:
+    def fib(self, n: int) -> int:
+        if n == 0:
+            print(0)
+        elif n == 1:
+            print(1)
+        c = 0
+        a = 0
+        b = 1
+        for i in range(1,n):
+            c = a + b
+            a = b
+            b = c
+        return c
+