diff --git a/HamSungJun/Solution_1837.ts b/HamSungJun/Solution_1837.ts
new file mode 100644
index 0000000..02fc7e8
--- /dev/null
+++ b/HamSungJun/Solution_1837.ts
@@ -0,0 +1,3 @@
+function sumBase (n: number, k: number): number {
+  return n.toString(k).split('').reduce((acc, curr) => (acc += +curr), 0)
+};
diff --git a/HamSungJun/Solution_728.ts b/HamSungJun/Solution_728.ts
new file mode 100644
index 0000000..83987ee
--- /dev/null
+++ b/HamSungJun/Solution_728.ts
@@ -0,0 +1,21 @@
+function selfDividingNumbers (left: number, right: number): number[] {
+  const answers = []
+  for (let i = left; i <= right; i++) {
+    if (isSelfDivide(i)) {
+      answers.push(i)
+    }
+  }
+  return answers
+};
+
+function isSelfDivide (num: number): boolean {
+  let numCopy = num
+  while (numCopy > 0) {
+    const nextDivider = numCopy % 10
+    if (num % nextDivider !== 0) {
+      return false
+    }
+    numCopy = Math.floor(numCopy / 10)
+  }
+  return true
+}
diff --git a/HamSungJun/Solution_942.ts b/HamSungJun/Solution_942.ts
new file mode 100644
index 0000000..62eebaa
--- /dev/null
+++ b/HamSungJun/Solution_942.ts
@@ -0,0 +1,22 @@
+function diStringMatch (s: string): number[] {
+  let cursor = 0
+  let p1 = 0
+  let p2 = s.length
+  const answer = []
+  while (p1 <= p2 && cursor < s.length) {
+    const nextStr = s[cursor]
+    switch (nextStr) {
+      case 'I':
+        answer.push(p1++)
+        break
+      case 'D':
+        answer.push(p2--)
+        break
+    }
+    cursor += 1
+  }
+  answer.push(p1)
+  return answer
+};
+
+console.log(diStringMatch('IDID'))