Submission #1955506

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Source Code Expand

package tester;

import java.util.Arrays;
import java.util.Scanner;

class Main {
	int n;
	int[] a;
	int[] b;
	final long MOD = 1_000_000_000 + 7;

	void run() {
		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();
		a = new int[n];
		b = new int[n];
		for (int i = 0; i < n; ++i) {
			a[i] = sc.nextInt();
		}
		for (int i = 0; i < n; ++i) {
			b[i] = sc.nextInt();
		}
		Arrays.sort(a);
		Arrays.sort(b);
		long[] c = new long[2 * n];
		for (int i = 0; i < n; ++i) {
			c[2 * i] = 2 * a[i];
			c[2 * i + 1] = 2 * b[i] + 1;
		}
		Arrays.sort(c);
		int p = 0, q = 0;
		long ans = 1;
		for (int i = 0; i < 2 * n; ++i) {
			if (c[i] % 2 == 1) {// outlet
				if (p == 0) {
					++q;
				} else {
					ans = ans * p % MOD;
					--p;
				}
			} else {// pc
				if (q == 0)
					++p;
				else {
					--q;
				}
			}
		}
		System.out.println(ans);
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}

	public static void main(String[] args) {
		new Main().run();
	}
}

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