easy 70 part 1

.gitignore

@@ -1 +1,2 @@
-venv
+venv
+__pycache__

src/easy/70-climbing-stairs/stairs.py

@@ -0,0 +1,28 @@
+# https://leetcode.com/problems/climbing-stairs/
+
+class Solution:
+    def climbStairs(self, n: int) -> int:
+        combos = 0
+        max_pairs = n // 2
+
+        for pairs in range(max_pairs + 1):
+            # trying combinations with i pairs of two
+            combos += self.combinations(pairs, n)
+
+        return combos
+
+    def combinations(self, pairs: int, positions: int) -> int:
+        # how many combinations to fit pairs pairs into positions?
+        if (pairs <= 0):
+            return 1
+
+        combos = 0
+
+        for i in range(positions - 1):
+            # start with pair and check all other combinations
+            combos += self.combinations(pairs-1, positions - (i+2))
+
+        return combos
+
+# TODO exceeds timelimit since values get calculated recursively miltiple times
+#  => memoization?

src/easy/70-climbing-stairs/test_stairs.py

@@ -0,0 +1,53 @@
+from stairs import Solution
+
+
+class TestStairs:
+    def test_one(self):
+        # x
+        assert Solution().climbStairs(1) == 1
+
+    def test_two(self):
+        # x x
+        # xx
+        assert Solution().climbStairs(2) == 2
+
+    def test_three(self):
+        # x x x
+        # xx x
+        # x xx
+        assert Solution().climbStairs(3) == 3
+
+    def test_four(self):
+        # x x x x
+        # xx x x
+        # x xx x
+        # x x xx
+        # xx xx
+        assert Solution().climbStairs(4) == 5
+
+    def test_five(self):
+        # x x x x x
+        # xx x x x
+        # x xx x x
+        # x x xx x
+        # x x x xx
+        # xx xx x
+        # xx x xx
+        # x xx xx
+        assert Solution().climbStairs(5) == 8
+
+    def test_six(self):
+        # x x x x x x
+        # xx x x x x
+        # x xx x x x
+        # x x xx x x
+        # x x x xx x
+        # x x x x xx
+        # xx xx x x
+        # xx x xx x
+        # xx x x xx
+        # x xx xx x
+        # x xx x xx
+        # x x xx xx
+        # xx xx xx
+        assert Solution().climbStairs(6) == 13