[20251101] BOJ / D5 / Hierarchical Structure / 권혁준

khj20006/202511/01 BOJ D5 Hierarchical Structure.md

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+```java
+import java.io.*;
+import java.util.*;
+
+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);
+	}
+
+}
+
+class SegTree {
+	int size;
+	long[] tree;
+	SegTree(int size) {
+		this.size = size;
+		tree = new long[size*4];
+	}
+
+	void upt(int s, int e, int i, int v, int n) {
+		if(s == e) {
+			tree[n] += v;
+			return;
+		}
+		int m = (s+e)>>1;
+		if(i <= m) upt(s,m,i,v,n*2);
+		else upt(m+1,e,i,v,n*2+1);
+		tree[n] = tree[n*2] + tree[n*2+1];
+	}
+
+	long sum(int s, int e, int l, int r, int n) {
+		if(l>r || l>e || r<s) return 0;
+		if(l<=s && e<=r) return tree[n];
+		int m = (s+e)>>1;
+		return sum(s,m,l,r,n*2) + sum(m+1,e,l,r,n*2+1);
+	}
+}
+
+public class Main {
+
+	static IOController io;
+
+	//
+
+	static int N, Q, root, cnt = 0;
+	static SegTree seg;
+	static TreeSet<Integer> lower;
+	static int[][] events, infos, queries;
+	static List<Integer>[] graph, chain;
+	static int[] sz, par, dep, cn, ci, ord;
+	static long[] ans;
+
+	static void dfs(int n, int p) {
+		sz[n] = 1;
+		par[n] = p;
+		for(int i:graph[n]) {
+			dfs(i,n);
+			sz[n] += sz[i];
+		}
+	}
+
+	static void hld(int n, int p, int s, int d) {
+		dep[n] = d;
+		cn[n] = s;
+		ci[n] = chain[s].size();
+		chain[s].add(n);
+		ord[n] = ++cnt;
+		int h = -1;
+		for(int i:graph[n]) if(h == -1 || sz[i] > sz[h]) h = i;
+		if(h != -1) hld(h,n,s,d);
+		for(int i:graph[n]) if(i != h) hld(i,n,i,d+1);
+	}
+
+	public static void main(String[] args) throws Exception {
+
+		io = new IOController();
+
+		N = io.nextInt();
+		Q = io.nextInt();
+
+		infos = new int[N][];
+		for(int i=1;i<=N;i++) infos[i-1] = new int[]{io.nextInt(),i};
+		Arrays.sort(infos, (a,b) -> a[0]==b[0] ? a[1]-b[1] : a[0]-b[0]);
+
+		graph = new List[N+1];
+		lower = new TreeSet<>();
+		for(int i=1;i<=N;i++) lower.add(i);
+		for(int i=1;i<=N;i++) graph[i] = new ArrayList<>();
+		for(int i=1;i<N;i++) {
+			int a = io.nextInt();
+			int b = io.nextInt();
+			graph[a].add(b);
+			lower.remove(b);
+		}
+		root = lower.higher(0);
+
+		events = new int[2*Q][];
+		queries = new int[Q][];
+		for(int i=0;i<Q;i++) {
+			int a = io.nextInt();
+			int b = io.nextInt();
+			int l = io.nextInt();
+			int r = io.nextInt();
+			events[i*2] = new int[]{l, i, -1};
+			events[i*2+1] = new int[]{r+1, i, 1};
+			queries[i] = new int[]{a,b,l,r};
+		}
+		Arrays.sort(events, (a,b) -> a[0]==b[0] ? a[1]-b[1] : a[0]-b[0]);
+
+		sz = new int[N+1];
+		par = new int[N+1];
+		dep = new int[N+1];
+		cn = new int[N+1];
+		ci = new int[N+1];
+		ord = new int[N+1];
+		chain = new List[N+1];
+		for(int i=1;i<=N;i++) chain[i] = new ArrayList<>();
+		dfs(root,0);
+		hld(root,0,root,0);
+
+		ans = new long[N];
+		seg = new SegTree(N+1);
+		int pos = 0;
+		for(int[] event : events) {
+			int value = event[0], queryIdx = event[1], coef = event[2];
+			while(pos < N && infos[pos][0] < value) {
+				seg.upt(1,N,ord[infos[pos][1]], infos[pos][0], 1);
+				pos++;
+			}
+
+			int a = queries[queryIdx][0];
+			int b = queries[queryIdx][1];
+			while(cn[a] != cn[b]) {
+				if(dep[a] > dep[b]) {
+					long sum = seg.sum(1,N,ord[cn[a]],ord[a],1);
+					ans[queryIdx] += sum * coef;
+					a = par[cn[a]];
+				}
+				else {
+					long sum = seg.sum(1,N,ord[cn[b]],ord[b],1);
+					ans[queryIdx] += sum * coef;
+					b = par[cn[b]];
+				}
+			}
+			if(ci[a] > ci[b]) {
+				long sum = seg.sum(1,N,ord[b],ord[a],1);
+				ans[queryIdx] += sum * coef;
+			}
+			else {
+				long sum = seg.sum(1,N,ord[a],ord[b],1);
+				ans[queryIdx] += sum * coef;
+			}
+		}
+
+		for(int i=0;i<Q;i++) io.write(ans[i] + "\n");
+
+		io.close();
+
+	}
+
+}
+```