[20250911] BOJ / G2 / 철로 / 김민진

Author: zinnnn37

zinnnn37/202509/11 BOJ G2 철로.md

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+```java
+import java.io.*;
+import java.util.Arrays;
+import java.util.PriorityQueue;
+import java.util.Queue;
+import java.util.StringTokenizer;
+
+public class BJ_13334_철로 {
+
+	private static final BufferedReader  br = new BufferedReader(new InputStreamReader(System.in));
+	private static final BufferedWriter  bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	private static       StringTokenizer st;
+
+	private static int n;
+	private static int d;
+	private static int ans;
+
+	private static Node[]         nodes;
+	private static Queue<Integer> q;
+
+	private static class Node implements Comparable<Node> {
+		int h;
+		int o;
+
+		Node(int h, int o) {
+			this.h = h;
+			this.o = o;
+		}
+
+		@Override
+		public int compareTo(Node o) {
+			if (this.o == o.o) {
+				return Integer.compare(this.h, o.h);
+			}
+			return Integer.compare(this.o, o.o);
+		}
+
+		@Override
+		public String toString() {
+			return "[h=" + h + ", o=" + o + "]";
+		}
+	}
+
+	public static void main(String[] args) throws IOException {
+		init();
+		sol();
+	}
+
+	private static void init() throws IOException {
+		n     = Integer.parseInt(br.readLine());
+		q     = new PriorityQueue<>();
+		ans   = 0;
+		nodes = new Node[n];
+
+		for (int i = 0; i < n; i++) {
+			st = new StringTokenizer(br.readLine());
+			int h = Integer.parseInt(st.nextToken());
+			int o = Integer.parseInt(st.nextToken());
+
+			if (h > o) {
+				nodes[i] = new Node(o, h);
+			} else {
+				nodes[i] = new Node(h, o);
+			}
+		}
+		d = Integer.parseInt(br.readLine());
+		Arrays.sort(nodes);
+	}
+
+	private static void sol() throws IOException {
+		for (int i = 0; i < n; i++) {
+			// 집-회사 거리가 d보다 큼
+			if (nodes[i].o - nodes[i].h > d) {
+				continue;
+			}
+
+			// 시작점 저장
+			q.offer(nodes[i].h);
+
+			// 철로 시작점 ~ 회사(도착지) 거리가 d 안쪽인 경우 철로에 포함되는 것
+			while (!q.isEmpty() && nodes[i].o - q.peek() > d) {
+				q.poll();
+			}
+			ans = Math.max(ans, q.size());
+		}
+		bw.write(ans + "");
+		bw.flush();
+		bw.close();
+		br.close();
+	}
+
+}
+```