Add soltuion for neetcode: staircase

neetcode/recursion/climbing_stairs/README.md

@@ -0,0 +1,26 @@
+You are given an integer n representing the number of steps to reach the top of a staircase. You can climb with either 1 or 2 steps at a time.
+
+Return the number of distinct ways to climb to the top of the staircase.
+
+Example 1:
+
+Input: n = 2
+
+Output: 2
+Explanation:
+
+1 + 1 = 2
+2 = 2
+Example 2:
+
+Input: n = 3
+
+Output: 3
+Explanation:
+
+1 + 1 + 1 = 3
+1 + 2 = 3
+2 + 1 = 3
+Constraints:
+
+1 <= n <= 30

neetcode/recursion/climbing_stairs/solution.py

@@ -0,0 +1,14 @@
+class Solution:
+    def climbStairs(self, n: int) -> int:
+        if n == 0:
+            return 1
+        if n < 0:
+            return 0
+        return self.climbStairs(n - 1) + self.climbStairs(n - 2)
+
+
+if __name__ == "__main__":
+    s = Solution()
+    print(s.climbStairs(5))
+    print(s.climbStairs(30))
+    print(s.climbStairs(1))