feat(leetcode/70): Climbing Stairs (Easy)

Author: renovizee

climbing-stairs/renovizee.java

@@ -1,17 +1,35 @@
 
 
+
 // tag renovizee 2week
 // https://github.com/DaleStudy/leetcode-study/issues/230
 // https://leetcode.com/problems/climbing-stairs/ #70 #Easy
 class Solution {
-    // Solv1 :
+    // Solv1
     // 시간복잡도 : O(n)
     // 공간복잡도 : O(n)
     public int climbStairs(int n) {
+        int[] dp = new int[]{1, 2};
+
+        if (n == dp[0]) {
+            return dp[0];
+        }
+
+        if (n == dp[1]) {
+            return dp[1];
+        }
+
+        for (int i = 3; i <= n; i++) {
+            int nextWayCount = dp[0] + dp[1];
+            dp[0] = dp[1];
+            dp[1] = nextWayCount;
+        }
+
+        return dp[1];
 
     }
 }
 //-------------------------------------------------------------------------------------------------------------
 // Java 문법 피드백
-//
+// 1) Math.pow(2, 3) 2의 3승.
 //-------------------------------------------------------------------------------------------------------------