climbing-stairs solution

Author: kimjunyoung90

climbing-stairs/kimjunyoung90.java

@@ -0,0 +1,16 @@
+public class kimjunyoung90 {
+    public int climbStairs(int n) {
+        if(n == 1) return 1;
+        if(n == 2) return 2;
+
+        int a = 1;
+        int b = 2;
+
+        for(int i = 3; i <= n; i++) {
+            int c = a + b;
+            a = b;
+            b = c;
+        }
+        return b;
+    }
+}