[20251129] BOJ / G5 / 선 긋기 / 이준희

JHLEE325/202511/29 BOJ G5 선 긋기.md

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+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static class line {
+        int x, y;
+        line(int x, int y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st;
+        int N = Integer.parseInt(br.readLine());
+
+        line[] arr = new line[N];
+
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            int a = Integer.parseInt(st.nextToken());
+            int b = Integer.parseInt(st.nextToken());
+
+            if (a > b) {
+                int temp = a;
+                a = b;
+                b = temp;
+            }
+
+            arr[i] = new line(a, b);
+        }
+
+        Arrays.sort(arr, (o1, o2) -> {
+            if (o1.x == o2.x) return o1.y - o2.y;
+            return o1.x - o2.x;
+        });
+
+        long answer = 0;
+
+        int curStart = arr[0].x;
+        int curEnd = arr[0].y;
+
+        for (int i = 1; i < N; i++) {
+            int nx = arr[i].x;
+            int ny = arr[i].y;
+
+            if (nx <= curEnd) {
+                curEnd = Math.max(curEnd, ny);
+            } else {
+                answer += (curEnd - curStart);
+                curStart = nx;
+                curEnd = ny;
+            }
+        }
+
+        answer += (curEnd - curStart);
+
+        System.out.println(answer);
+    }
+}
+```