diff --git "a/hyeokbini/3020.\352\260\234\353\230\245\353\262\214\353\240\210/3020.cpp" "b/hyeokbini/3020.\352\260\234\353\230\245\353\262\214\353\240\210/3020.cpp"
new file mode 100644
index 0000000..bdbc055
--- /dev/null
+++ "b/hyeokbini/3020.\352\260\234\353\230\245\353\262\214\353\240\210/3020.cpp"
@@ -0,0 +1,97 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+// 종유석
+vector<int> top;
+// 석순
+vector<int> bottom;
+int n, h;
+int best = INT_MAX;
+int way = 0;
+
+// 인자로 주는 curheight는 0 based로
+void func(int curheight)
+{
+    int val = 0;
+    int needbottom = curheight + 1;
+    int needtop = h - curheight;
+
+    // 석순 계산
+    int start = 0;
+    int end = (n / 2) - 1;
+    int stand = n / 2; // 기본값
+    while(start <= end)
+    {
+        int mid = (start + end) / 2;
+        if(bottom[mid] >= needbottom)
+        {
+            stand = mid;
+            end = mid - 1;
+        }
+        else
+        {
+            start = mid + 1;
+        }
+    }
+    val += (n / 2) - stand;
+    // 종유석 계산
+    start = 0;
+    end = (n / 2) - 1;
+    stand = n / 2;
+    while(start <= end)
+    {
+        int mid = (start + end) / 2;
+        if(top[mid] >= needtop)
+        {
+            stand = mid;
+            end = mid - 1;
+        }
+        else
+        {
+            start = mid + 1;
+        }
+    }
+    val += (n/2) - stand;
+
+    // 갱신
+    if(best > val)
+    {
+        best = val;
+        way = 1;
+    }
+    else if(best == val)
+    {
+        way++;
+    }
+    return;
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(0);
+    //freopen("test.txt", "rt", stdin);
+    cin >> n >> h;
+    for(int i = 0; i < n; i++)
+    {
+        int val;
+        cin >> val;
+        if(i % 2 == 0)
+        {
+            bottom.push_back(val);
+        }
+        else
+        {
+            top.push_back(val);
+        }
+    }
+    sort(bottom.begin(),bottom.end());
+    sort(top.begin(),top.end());
+    for(int i = 0; i < h; i++)
+    {
+        func(i);
+    }
+    cout << best << " " << way;
+    return 0;
+}
diff --git a/hyeokbini/README.md b/hyeokbini/README.md
index 182728a..19e50ba 100644
--- a/hyeokbini/README.md
+++ b/hyeokbini/README.md
@@ -23,3 +23,4 @@
  | 19차시 | 2025.08.10 |  브루트포스  | [리모컨](https://www.acmicpc.net/problem/1107)|[#19](https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/68)|
  | 20차시 | 2025.08.14 |  완전탐색,DFS  | [모음사전](https://school.programmers.co.kr/learn/courses/30/lessons/84512)|[#20](https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/72)|
  | 21차시 | 2025.08.19 |  브루트포스  | [제곱수 찾기](https://www.acmicpc.net/problem/1025)|[#21](https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/76)|
+ | 23차시 | 2025.08.27 |  이분 탐색  | [개똥벌레](https://www.acmicpc.net/problem/3020)|[#23](https://github.com/AlgoLeadMe/AlgoLeadMe-15/pull/80)|
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