이지영: [BOJ] 2170 선 긋기_250208

Author: yeongleej

BOJ/1000-5000번/JY_2170.java

@@ -0,0 +1,66 @@
+import java.io.*;
+import java.util.*;
+public class JY_2170 {
+	
+	static class Pos implements Comparable<Pos> {
+		int x, y;
+
+		public Pos(int x, int y) {
+			super();
+			this.x = x;
+			this.y = y;
+		}
+		@Override
+		public int compareTo(Pos other) {
+			return this.x - other.x;
+		}
+
+		@Override
+		public String toString() {
+			return "Pos [x=" + x + ", y=" + y + "]";
+		}
+		
+	}
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st = new StringTokenizer(br.readLine());
+		
+		int N = Integer.parseInt(st.nextToken());
+		
+		List<Pos> pList = new ArrayList<>();
+		for(int i=0; i<N; i++) {
+			st = new StringTokenizer(br.readLine());
+			int x = Integer.parseInt(st.nextToken());
+			int y = Integer.parseInt(st.nextToken());
+			
+			pList.add(new Pos(x, y));
+		}
+		
+		// x기준으로 정렬
+		Collections.sort(pList);
+		
+		int s = pList.get(0).x;
+		int e = pList.get(0).y;
+		int ans = 0;
+		for(int i=1; i<N; i++) {
+			Pos now = pList.get(i);
+			
+			// now.x가 end보다 작다면 겹침 -> end 갱신
+			if(e >= now.x) {
+				e = Math.max(e, now.y);
+			}
+			// 겹치지 않는 경우
+			else {
+				// 기존것 더해주고 새로 업데이트
+				ans += (e - s);
+				s = now.x;
+				e = now.y;
+			}
+		}
+		ans += (e - s);
+		System.out.println(ans);
+
+	}
+
+}