solves fibonacci number

Author: anishLearnsToCode

README.md

@@ -136,7 +136,7 @@
 | 504 | [Base 7](https://leetcode.com/problems/base-7) | Easy | [![Java](assets/java.png)](src/Base7.java) [![Python](assets/python.png)](python/base_7.py) |
 | 506 | [Relative Ranks](https://leetcode.com/problems/relative-ranks) | Easy | [![Java](assets/java.png)](src/RelativeRanks.java) [![Python](assets/python.png)](python/relative_ranks.py) |
 | 507 | [Perfect Number](https://leetcode.com/problems/perfect-number) | Easy | [![Java](assets/java.png)](src/CheckPerfectNumber.java) [![Python](assets/python.png)](python/check_perfect_number.py) |
-| 509 | [Fibonacci Number](https://leetcode.com/problems/fibonacci-number) | Easy | |
+| 509 | [Fibonacci Number](https://leetcode.com/problems/fibonacci-number) | Easy | [![Java](assets/java.png)](src/FibonacciNumber.java) [![Python](assets/python.png)](python/fibonacci_number.py) |
 | 520 | [Detect Capital](https://leetcode.com/problems/detect-capital) | Easy | |
 | 521 | [Longest Uncommon Subsequence I](https://leetcode.com/problems/longest-uncommon-subsequence-i) | Easy | |
 | 530 | [Minimum Absolute Difference in BST](https://leetcode.com/problems/minimum-absolute-difference-in-bst) | Easy | |

python/fibonacci_number.py

@@ -0,0 +1,6 @@
+class Solution:
+    def fib(self, n: int) -> int:
+        prev, current = 0, 1
+        for i in range(n):
+            prev, current = current, prev + current
+        return prev

src/FibonacciNumber.java

@@ -0,0 +1,11 @@
+public class FibonacciNumber {
+    public int fib(int n) {
+        int previous = 0, current = 1, temp1;
+        for (int i = 0 ; i < n ; i++) {
+            temp1 = current;
+            current = previous + current;
+            previous = temp1;
+        }
+        return previous;
+    }
+}