Merge pull request #505 from AlgorithmWithGod/03do-new30

[20250720] BOJ / G4 / 작업 / 신동윤

Author: ShinHeeEul

03do-new30/202507/20 BOJ G4 작업.md

@@ -0,0 +1,64 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class Main {
+    static int N;
+    static int[] indegree; // 차수 저장
+    static int[] time; // 시간 저장
+    static List<Integer>[] adjList; // 인접 리스트
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        N = Integer.parseInt(br.readLine());
+        indegree = new int[N+1];
+        time = new int[N+1];
+        adjList = new List[N+1];
+        for (int i = 1; i <= N; i++) {
+            adjList[i] = new ArrayList<>();
+        }
+
+        for (int i = 1; i <= N; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            time[i] = Integer.parseInt(st.nextToken());
+
+            int cnt = Integer.parseInt(st.nextToken());
+            for (int j = 0; j < cnt; j++) {
+                int prevId = Integer.parseInt(st.nextToken());
+                adjList[prevId].add(i);
+                ++indegree[i];
+            }
+        }
+        int ans = topologicalSort();
+        System.out.println(ans);
+        br.close();
+    }
+
+    private static int topologicalSort() {
+
+        Queue<Integer> q = new ArrayDeque<>();
+        int[] visitTime = new int[N+1];
+
+        for (int i = 1; i <= N; i++) {
+            visitTime[i] = time[i];
+            if (indegree[i] == 0) q.offer(i);
+        }
+
+        while (!q.isEmpty()) {
+            int current = q.poll();
+            for (int next : adjList[current]) {
+                visitTime[next] = Math.max(visitTime[next], visitTime[current] + time[next]);
+                if (--indegree[next] == 0) {
+                    q.offer(next);
+                }
+            }
+        }
+
+        int ret = 0;
+        for (int i = 1; i <= N; i++) {
+            ret = Math.max(ret, visitTime[i]);
+        }
+        return ret;
+    }
+}
+
+```