feat: 70_climbing_stairs

70_climbing_stairs/main.cpp

@@ -0,0 +1,20 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+   public:
+    int fibonacci_1(int a, int b, int n) {
+        if (n <= 1) return b;
+        return fibonacci_1(b, a + b, n - 1);
+    }
+
+    int fibonacci_2(int n) {
+        if (n == 2) return 2;
+        if (n == 1) return 1;
+        return fibonacci_2(n - 1) + fibonacci_2(n - 2);
+    }
+
+    int climbStairs(int n) {
+        return fibonacci_1(1, 1, n);
+    }
+};