diff --git a/longest-common-subsequence/YeomChaeeun.ts b/longest-common-subsequence/YeomChaeeun.ts
new file mode 100644
index 000000000..1a4dd624a
--- /dev/null
+++ b/longest-common-subsequence/YeomChaeeun.ts
@@ -0,0 +1,24 @@
+/**
+ * 가장 긴 공통 부분 수열 구하기
+ * 알고리즘 복잡도
+ * - 시간 복잡도: O(m*n)
+ * - 공간 복잡도: O(m*n)
+ * @param text1
+ * @param text2
+ */
+function longestCommonSubsequence(text1: string, text2: string): number {
+    let dp: number[][] = Array(text1.length + 1).fill(0)
+        .map(() => Array(text2.length + 1).fill(0));
+
+    for(let i = 1; i <= text1.length; i++) {
+        for(let j = 1; j <= text2.length; j++) {
+            if(text1[i-1] === text2[j-1]) {
+                dp[i][j] = dp[i-1][j-1] + 1;
+            } else {
+                dp[i][j] = Math.max(dp[i-1][j], dp[i][j-1]);
+            }
+        }
+    }
+
+    return dp[text1.length][text2.length];
+}
diff --git a/number-of-1-bits/YeomChaeeun.ts b/number-of-1-bits/YeomChaeeun.ts
new file mode 100644
index 000000000..d1fbec020
--- /dev/null
+++ b/number-of-1-bits/YeomChaeeun.ts
@@ -0,0 +1,17 @@
+/**
+ * 10진수 n이 2진수일 때 1을 세기
+ * 알고리즘 복잡도
+ * - 시간 복잡도: O(logn)
+ * - 공간 복잡도: O(logn)
+ * @param n
+ */
+function hammingWeight(n: number): number {
+    let binary = "";
+
+    while(n > 0) {
+        binary = (n % 2) + binary;
+        n = Math.floor(n / 2);
+    }
+
+    return [...binary].filter(val => val === '1').length
+}
diff --git a/sum-of-two-integers/YeomChaeeun.ts b/sum-of-two-integers/YeomChaeeun.ts
new file mode 100644
index 000000000..e386ae666
--- /dev/null
+++ b/sum-of-two-integers/YeomChaeeun.ts
@@ -0,0 +1,17 @@
+/**
+ * 연산자 + 사용하지 않고 덧셈하기
+ * 알고리즘 복잡도
+ * - 시간 복잡도: O(logn) - 비트 수만큼 계산
+ * - 공간 복잡도: O(1)
+ * @param a
+ * @param b
+ */
+function getSum(a: number, b: number): number {
+    while(b !== 0) {
+        let carry = a & b; // and - 11 & 10 = 10
+        a = a ^ b; // xor - 11 ^ 10 = 01
+        b = carry << 1; // 100
+    }
+
+    return a
+}