From 432d7a68e80a03aaebb9f40a39b2d6ae548255a7 Mon Sep 17 00:00:00 2001
From: Jonghwan Lee <123362165+0224LJH@users.noreply.github.com>
Date: Mon, 15 Sep 2025 21:51:01 +0900
Subject: [PATCH] =?UTF-8?q?[20250915]=20BOJ=20/=20G2=20/=20=EB=AC=B8?=
 =?UTF-8?q?=EC=A0=9C=EC=A7=91=20/=20=EC=9D=B4=EC=A2=85=ED=99=98?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 ...J \353\254\270\354\240\234\354\247\221.md" | 83 +++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 "0224LJH/202509/15 BOJ \353\254\270\354\240\234\354\247\221.md"

diff --git "a/0224LJH/202509/15 BOJ \353\254\270\354\240\234\354\247\221.md" "b/0224LJH/202509/15 BOJ \353\254\270\354\240\234\354\247\221.md"
new file mode 100644
index 00000000..27f35eb7
--- /dev/null
+++ "b/0224LJH/202509/15 BOJ \353\254\270\354\240\234\354\247\221.md"	
@@ -0,0 +1,83 @@
+```java
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.*;
+
+public class Main {
+	static int nodeCnt, infoCnt;
+	static Node[] nodes;
+	static StringBuilder sb = new StringBuilder();
+	static class Node implements Comparable<Node>{
+		int num;
+		int beforeCnt = 0; // 이 노드 전에 나와야 하는 노드 수
+		HashSet<Node> after = new HashSet<>();
+		
+		
+		
+		public Node(int num) {
+			this.num = num;
+		}
+		
+		@Override
+		public int compareTo(Node n) {
+			return Integer.compare(this.num, n.num);
+		}
+	}
+
+    
+    public static void main(String[] args) throws NumberFormatException, IOException {
+      init();
+      process();
+      print();
+    }
+
+	public static void init() throws NumberFormatException, IOException {
+    	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    	StringTokenizer st = new StringTokenizer(br.readLine());
+    	nodeCnt =Integer.parseInt(st.nextToken());
+    	infoCnt = Integer.parseInt(st.nextToken());
+    	nodes = new Node[nodeCnt+1];
+    	
+    	for (int i = 1 ; i <= nodeCnt; i++) nodes[i] = new Node(i);
+    	for (int i = 0; i < infoCnt; i++) {
+    		st = new StringTokenizer(br.readLine());
+    		int before = Integer.parseInt(st.nextToken());
+    		int after = Integer.parseInt(st.nextToken());
+    		
+    		nodes[after].beforeCnt++;
+    		nodes[before].after.add(nodes[after]);
+    	}
+
+    }
+    
+    public static void process() {   
+    	PriorityQueue<Node> pq = new PriorityQueue<>();
+    	for (int i = 1; i<= nodeCnt; i++) {
+    		if (nodes[i].beforeCnt != 0 )continue;
+    		pq.add(nodes[i]);
+    	}
+    	
+    	while(!pq.isEmpty()) {
+    		Node n =pq.poll();
+    		if ( n.beforeCnt != 0) {
+    			pq.add(n);
+    			continue;
+    		}
+    		
+    		sb.append(n.num).append(" ");
+    		
+    		for (Node b: n.after) {
+    			b.beforeCnt--;
+    			if (b.beforeCnt == 0) pq.add(b);
+    		}
+    	}
+    	
+    }
+
+
+	public static void print() {
+    	System.out.println(sb.toString());
+    }
+}
+```