feat: climbing stairs

Author: minji-go

climbing-stairs/minji-go.java

@@ -0,0 +1,18 @@
+/*
+    Problem: https://leetcode.com/problems/climbing-stairs/
+    Description: how many distinct ways can you climb to the top, if you can either climb 1 or 2 steps
+    Concept: Dynamic Programming, Memoization, Recursion, Math, Array, Iterator, Combinatorics ...
+    Time Complexity: O(n), Runtime: 0ms
+    Space Complexity: O(1), Memory: 40.51MB
+*/
+class Solution {
+    public int climbStairs(int n) {
+        int step1=1, step2=2;
+        for(int i=3; i<n; i++){
+            int step3=step1+step2;
+            step1=step2;
+            step2=step3;
+        }
+        return n==1?step1:step2;
+    }
+}