241024 ATM

static int n;
static int m;
static int cnt;
static int sccCount;
static ArrayList<Integer>[] adj;
static int[] dfsn;
static int[] sccId;
static int[] sIndegree;
static int[] cash;
static int[] sCash;
static int[] sMax;
static boolean[] finished;
static boolean[] rest;
static boolean[] sRest;
static boolean[] sPath;
static Stack<Integer> stack = new Stack<>();
static ArrayList<Integer>[] sAdj;
static int start;

@SuppressWarnings("unchecked")
public static void main(String[] args) throws IOException {
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	StringTokenizer st = new StringTokenizer(br.readLine());

	n = Integer.parseInt(st.nextToken());
	m = Integer.parseInt(st.nextToken());

	adj = new ArrayList[n + 1];
	for (int i = 1; i <= n; i++) adj[i] = new ArrayList<>();

	dfsn = new int[n + 1];
	finished = new boolean[n + 1];
	sccId = new int[n + 1];

	for (int i = 0; i < m; i++) {
		st = new StringTokenizer(br.readLine());
		int u = Integer.parseInt(st.nextToken());
		int v = Integer.parseInt(st.nextToken());
		adj[u].add(v);
	}

	cash = new int[n + 1];
	for (int i = 1; i <= n; i++) {
		cash[i] = Integer.parseInt(br.readLine());
	}

	st = new StringTokenizer(br.readLine());
	start = Integer.parseInt(st.nextToken());
	int restCount = Integer.parseInt(st.nextToken());

	rest = new boolean[n + 1];
	st = new StringTokenizer(br.readLine());
	for (int i = 0; i < restCount; i++) {
		int r = Integer.parseInt(st.nextToken());
		rest[r] = true;
	}

	for (int i = 1; i <= n; i++) {
		if (dfsn[i] == 0) findSCC(i);
	}

	sAdj = new ArrayList[sccCount + 1];
	sIndegree = new int[sccCount + 1];
	sRest = new boolean[sccCount + 1];
	sCash = new int[sccCount + 1];
	sMax = new int[sccCount + 1];
	sPath = new boolean[sccCount + 1];

	for (int i = 1; i <= sccCount; i++) sAdj[i] = new ArrayList<>();

	for (int i = 1; i <= n; i++) {
		int currentSCC = sccId[i];
		sCash[currentSCC] += cash[i];
		sMax[currentSCC] = sCash[currentSCC];
		if (rest[i]) sRest[currentSCC] = true;
		if (i == start) sPath[currentSCC] = true;

		for (int next : adj[i]) {
			int nextSCC = sccId[next];
			if (currentSCC != nextSCC && !sAdj[currentSCC].contains(nextSCC)) {
				sAdj[currentSCC].add(nextSCC);
				sIndegree[nextSCC]++;
			}
		}
	}

	Queue<Integer> queue = new LinkedList<>();
	for (int i = 1; i <= sccCount; i++) {
		if (sIndegree[i] == 0) queue.offer(i);
	}

	while (!queue.isEmpty()) {
		int currSCC = queue.poll();
		for (int nextSCC : sAdj[currSCC]) {
			if (sPath[currSCC]) {
				sMax[nextSCC] = Math.max(sMax[nextSCC], sMax[currSCC] + sCash[nextSCC]);
				sPath[nextSCC] = true;
			}
			if (--sIndegree[nextSCC] == 0) queue.offer(nextSCC);
		}
	}

	int result = 0;
	for (int i = 1; i <= sccCount; i++) {
		if (sRest[i] && sPath[i]) result = Math.max(result, sMax[i]);
	}
	System.out.println(result);
}

public static int findSCC(int curr) {
	dfsn[curr] = ++cnt;
	stack.push(curr);
	int lowLink = dfsn[curr];

	for (int next : adj[curr]) {
		if (dfsn[next] == 0) lowLink = Math.min(lowLink, findSCC(next));
		else if (!finished[next]) lowLink = Math.min(lowLink, dfsn[next]);
	}

	if (lowLink == dfsn[curr]) {
		sccCount++;
		while (true) {
			int node = stack.pop();
			finished[node] = true;
			sccId[node] = sccCount;
			if (node == curr) break;
		}
	}
	return lowLink;
}

출처:https://www.acmicpc.net/problem/4013