diff --git a/climbing-stairs/changchanghwang.go b/climbing-stairs/changchanghwang.go
new file mode 100644
index 000000000..5645c9d5d
--- /dev/null
+++ b/climbing-stairs/changchanghwang.go
@@ -0,0 +1,10 @@
+// Time complexity, O(n)
+// Space complexity, O(1)
+// 피보나치 수열로 풀이가 가능하다.
+func climbStairs(n int) int {
+	a, b := 1, 1
+	for ; n > 1; n-- {
+		a, b = b, a+b
+	}
+	return b
+}
diff --git a/valid-anagram/changchanghwang.go b/valid-anagram/changchanghwang.go
new file mode 100644
index 000000000..8b2cc67d2
--- /dev/null
+++ b/valid-anagram/changchanghwang.go
@@ -0,0 +1,24 @@
+// Time complexity, O(n)
+// Space complexity, O(1)
+func isAnagram(s string, t string) bool {
+	if len(s) != len(t) {
+		return false
+	}
+	count := make([]int, 26)
+
+	for index, _ := range count {
+		count[index] = 0
+	}
+
+	for i := 0; i < len(s); i++ {
+		count[int(s[i])-int('a')]++ // s의 문자를 카운트하고
+		count[int(t[i])-int('a')]-- // a의 문자를 -1 한다.
+	}
+
+	for _, val := range count {
+		if val != 0 { // 0이 아니라면 다른 문자열이 있는것이기 때문에 false
+			return false
+		}
+	}
+	return true
+}