diff --git "a/khj20006/202508/30 BOJ P4 \353\266\200\353\252\250\353\213\230\352\273\230 \355\201\260\354\240\210 \355\225\230\352\263\240.md" "b/khj20006/202508/30 BOJ P4 \353\266\200\353\252\250\353\213\230\352\273\230 \355\201\260\354\240\210 \355\225\230\352\263\240.md"
new file mode 100644
index 00000000..4a2e7ab7
--- /dev/null
+++ "b/khj20006/202508/30 BOJ P4 \353\266\200\353\252\250\353\213\230\352\273\230 \355\201\260\354\240\210 \355\225\230\352\263\240.md"	
@@ -0,0 +1,121 @@
+```java
+import java.util.*;
+import java.io.*;
+
+class IOController {
+	BufferedReader br;
+	BufferedWriter bw;
+	StringTokenizer st;
+
+	public IOController() {
+		br = new BufferedReader(new InputStreamReader(System.in));
+		bw = new BufferedWriter(new OutputStreamWriter(System.out));
+		st = new StringTokenizer("");
+	}
+
+	String nextLine() throws Exception {
+		String line = br.readLine();
+		st = new StringTokenizer(line);
+		return line;
+	}
+
+	String nextToken() throws Exception {
+		while (!st.hasMoreTokens()) nextLine();
+		return st.nextToken();
+	}
+
+	int nextInt() throws Exception {
+		return Integer.parseInt(nextToken());
+	}
+
+	long nextLong() throws Exception {
+		return Long.parseLong(nextToken());
+	}
+
+	double nextDouble() throws Exception {
+		return Double.parseDouble(nextToken());
+	}
+
+	void close() throws Exception {
+		bw.flush();
+		bw.close();
+	}
+
+	void write(String content) throws Exception {
+		bw.write(content);
+	}
+
+}
+
+public class Main {
+
+	static IOController io;
+
+	//
+
+	static int N;
+	static int[] a;
+
+	public static void main(String[] args) throws Exception {
+
+		io = new IOController();
+
+		N = io.nextInt();
+		a = new int[N];
+		int min = Integer.MAX_VALUE;
+		for(int i=0;i<N;i++) {
+			a[i] = io.nextInt();
+			min = Math.min(min, a[i]);
+		}
+
+		for(int i=0;i<N;i++) a[i] -= min;
+
+		Arrays.sort(a);
+		if(a[1] == 0) {
+			io.write("No");
+			io.close();
+			return;
+		}
+		int last = a[1], d = a[1], c = 2;
+		boolean[] vis = new boolean[N];
+		for(int i=2;i<N;i++) {
+			if(a[i] == d*c) {
+				last = d*c;
+				c++;
+				vis[i] = true;
+			}
+		}
+
+		List<Integer> list = new ArrayList<>();
+		for(int i=2;i<N;i++) if(!vis[i]) list.add(a[i]);
+
+		d = list.get(0);
+		c = 2;
+		boolean can = true;
+		for(int i=1;i<list.size();i++) {
+			int cur = list.get(i);
+			if(cur == d*c) c++;
+			else can = false;
+		}
+
+		if(!can) {
+			list.add(last);
+			Collections.sort(list);
+			d = list.get(0);
+			c = 2;
+			can = true;
+			for(int i=1;i<list.size();i++) {
+				int cur = list.get(i);
+				if(cur == d*c) c++;
+				else can = false;
+			}
+		}
+
+		io.write(can ? "Yes" : "No");
+
+		io.close();
+
+	}
+
+}
+```