diff --git a/bona1122/[week4]Hash/Discount_event.js b/bona1122/[week4]Hash/Discount_event.js
new file mode 100644
index 0000000..25fc92f
--- /dev/null
+++ b/bona1122/[week4]Hash/Discount_event.js
@@ -0,0 +1,60 @@
+// 방법 1: 매번 slice로 새 배열과 객체를 생성
+function solution1(want, number, discount) {
+  let answer = 0
+  const map = want.reduce((map, name, idx) => {
+    map[name] = number[idx]
+    return map
+  }, {})
+
+  const check = (sale) => {
+    for (let item in map) {
+      if (map[item] !== sale[item]) return false
+    }
+    return true
+  }
+
+  for (let i = 0; i <= discount.length - 10; i++) {
+    const sliced = discount.slice(i, i + 10)
+    const sale = sliced.reduce((map, name) => {
+      map[name] = (map[name] || 0) + 1
+      return map
+    }, {})
+
+    if (check(sale)) answer++
+  }
+
+  return answer
+}
+
+// 방법 2: 슬라이딩 윈도우
+function solution2(want, number, discount) {
+  const need = want.reduce((obj, name, idx) => {
+    obj[name] = number[idx]
+    return obj
+  }, {})
+
+  // 초기 윈도우(첫 10일) 설정
+  const sale = {}
+  for (let i = 0; i < 10; i++) {
+    sale[discount[i]] = (sale[discount[i]] || 0) + 1
+  }
+
+  const check = () => {
+    for (let item in need) {
+      if (need[item] !== sale[item]) return false
+    }
+    return true
+  }
+
+  let answer = check() ? 1 : 0
+
+  // 슬라이딩 윈도우 이동
+  for (let i = 10; i < discount.length; i++) {
+    sale[discount[i]] = (sale[discount[i]] || 0) + 1 // 새로운 것 추가
+    sale[discount[i - 10]]-- // 이전 것 제거
+
+    if (check()) answer++
+  }
+
+  return answer
+}
diff --git a/bona1122/[week4]Hash/Incomplete_runner.js b/bona1122/[week4]Hash/Incomplete_runner.js
new file mode 100644
index 0000000..3089e1c
--- /dev/null
+++ b/bona1122/[week4]Hash/Incomplete_runner.js
@@ -0,0 +1,15 @@
+// 완주자 목록으로 해시맵 생성
+const solution = (participant, completion) => {
+  const completionMap = completion.reduce((map, person) => {
+    map[person] = (map[person] || 0) + 1
+    return map
+  }, {})
+
+  return participant.find((person) => {
+    if (completionMap[person]) {
+      completionMap[person]--
+      return false
+    }
+    return true
+  })
+}
diff --git a/bona1122/[week4]Hash/Keypad_press.js b/bona1122/[week4]Hash/Keypad_press.js
new file mode 100644
index 0000000..e9845b0
--- /dev/null
+++ b/bona1122/[week4]Hash/Keypad_press.js
@@ -0,0 +1,119 @@
+// 방법 1: 객체기반 접근(각 숫자의 좌표 직접 매핑 - 하드코딩)
+function solution1(numbers, hand) {
+  const keypad = {
+    1: [0, 0],
+    2: [0, 1],
+    3: [0, 2],
+    4: [1, 0],
+    5: [1, 1],
+    6: [1, 2],
+    7: [2, 0],
+    8: [2, 1],
+    9: [2, 2],
+    "*": [3, 0],
+    0: [3, 1],
+    "#": [3, 2],
+  }
+
+  let left = keypad["*"]
+  let right = keypad["#"]
+
+  const getDist = ([y1, x1], [y2, x2]) => Math.abs(y1 - y2) + Math.abs(x1 - x2)
+
+  return numbers
+    .map((num) => {
+      const target = keypad[num]
+
+      // 왼쪽 열이면, 왼손
+      if (target[1] === 0) {
+        left = target
+        return "L"
+      }
+      // 오른쪽 열이면, 오른손
+      if (target[1] === 2) {
+        right = target
+        return "R"
+      }
+
+      // 가운데열의 경우, 거리 비교
+      const leftDist = getDist(left, target)
+      const rightDist = getDist(right, target)
+
+      if (leftDist === rightDist) {
+        if (hand === "right") {
+          right = target
+          return "R"
+        }
+        left = target
+        return "L"
+      }
+
+      if (leftDist < rightDist) {
+        left = target
+        return "L"
+      } else {
+        right = target
+        return "R"
+      }
+    })
+    .join("")
+}
+
+// 방법 2: 2차원 배열로 실제 키패드 모양 표현 후, 좌표 매핑
+function solution2(numbers, hand) {
+  // 키패드를 2차원 배열로 정의
+  const keypad = [
+    [1, 2, 3],
+    [4, 5, 6],
+    [7, 8, 9],
+    ["*", 0, "#"],
+  ]
+
+  // 키패드를 좌표로 매핑
+  const getPos = new Map(
+    keypad.flatMap((row, y) => row.map((num, x) => [num, [y, x]]))
+  )
+
+  let left = getPos.get("*")
+  let right = getPos.get("#")
+
+  const getDist = ([y1, x1], [y2, x2]) => Math.abs(y1 - y2) + Math.abs(x1 - x2)
+
+  return numbers
+    .map((num) => {
+      const target = getPos.get(num)
+
+      // 왼쪽 열이면, 왼손
+      if (target[1] === 0) {
+        left = target
+        return "L"
+      }
+      // 오른쪽 열이면, 오른손
+      if (target[1] === 2) {
+        right = target
+        return "R"
+      }
+
+      // 가운데 열
+      const leftDist = getDist(left, target)
+      const rightDist = getDist(right, target)
+
+      if (leftDist === rightDist) {
+        if (hand === "right") {
+          right = target
+          return "R"
+        }
+        left = target
+        return "L"
+      }
+
+      if (leftDist < rightDist) {
+        left = target
+        return "L"
+      } else {
+        right = target
+        return "R"
+      }
+    })
+    .join("")
+}
diff --git a/bona1122/[week4]Hash/Memory_score.js b/bona1122/[week4]Hash/Memory_score.js
new file mode 100644
index 0000000..dc0ef45
--- /dev/null
+++ b/bona1122/[week4]Hash/Memory_score.js
@@ -0,0 +1,8 @@
+const solution = (name, yearning, photo) => {
+  const map = name.reduce((map, name, idx) => {
+    map[name] = yearning[idx]
+    return map
+  }, {})
+
+  return photo.map((p) => p.reduce((acc, cur) => (acc += map[cur] || 0), 0))
+}
diff --git a/bona1122/[week4]Hash/Open_chat.js b/bona1122/[week4]Hash/Open_chat.js
new file mode 100644
index 0000000..e65f816
--- /dev/null
+++ b/bona1122/[week4]Hash/Open_chat.js
@@ -0,0 +1,18 @@
+function solution(record) {
+  const userInfo = {}
+  const result = []
+  const MESSAGES = {
+    Enter: "님이 들어왔습니다.",
+    Leave: "님이 나갔습니다.",
+  }
+
+  record.forEach((r) => {
+    const [action, id, name] = r.split(" ")
+    if (name) userInfo[id] = name
+    if (action !== "Change") {
+      result.push([id, MESSAGES[action]])
+    }
+  })
+
+  return result.map(([id, message]) => userInfo[id] + message)
+}
diff --git a/bona1122/[week4]Hash/Phonekemon.js b/bona1122/[week4]Hash/Phonekemon.js
new file mode 100644
index 0000000..0476659
--- /dev/null
+++ b/bona1122/[week4]Hash/Phonekemon.js
@@ -0,0 +1,21 @@
+// 1. 해시맵을 이용한 풀이
+const solution1 = (nums) => {
+  let max = 0
+  const can = nums.length / 2
+  const map = nums.reduce((map, num) => {
+    if (map[num] === undefined) {
+      max++
+      map[num] = 1
+    }
+    return map
+  }, {})
+  return can < max ? can : max
+}
+
+// 2. Set을 이용한 풀이
+const solution2 = (nums) => {
+  const can = nums.length / 2
+  const max = [...new Set(nums)].length
+
+  return can < max ? can : max
+}