Submission #61385

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Source Code Expand

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

public class Main{

	int n, m, res;
	int[][] rail;
	boolean[] u;
	int[] c;
	
	void f(int k){
		if(k==m){
			boolean f = true;
			for(int i=1;i<=n;i++)f&=2<=c[i];
			if(f)res++;
			return;
		}
		f(k+1);
		for(int i=rail[k][0];i<=rail[k][1];i++)c[i]++;
		f(k+1);
		for(int i=rail[k][0];i<=rail[k][1];i++)c[i]--;
	}
	
	void run() {
		Scanner sc = new Scanner();
		n = sc.nextInt(); m = sc.nextInt();
		rail = new int[m][2];
		for(int i=0;i<m;i++)for(int j=0;j<2;j++)rail[i][j]=sc.nextInt();
		u = new boolean[m];
		c = new int[n+1];
		res = 0;
		f(0);
		System.out.println(res);
	}

	void debug(Object... o) {
		System.out.println(Arrays.deepToString(o));
	}
	
	class Scanner {
		int nextInt() {
			try {
				int c = System.in.read();
				while (c != '-' && (c < '0' || '9' < c))
					c = System.in.read();
				if (c == '-') return -nextInt();
				int res = 0;
				do {
					res *= 10;
					res += c - '0';
					c = System.in.read();
				} while ('0' <= c && c <= '9');
				return res;
			} catch (Exception e) {
				return -1;
			}
		}
		long nextLong() {
			try {
				int c = System.in.read();
				while (c != '-' && (c < '0' || '9' < c))
					c = System.in.read();
				if (c == '-') return -nextLong();
				long res = 0;
				do {
					res *= 10;
					res += c - '0';
					c = System.in.read();
				} while ('0' <= c && c <= '9');
				return res;
			} catch (Exception e) {
				return -1;
			}
		}
		double nextDouble() {
			return Double.parseDouble(next());
		}
		String next() {
			try {
				StringBuilder res = new StringBuilder("");
				int c = System.in.read();
				while (Character.isWhitespace(c))
					c = System.in.read();
				do {
					res.append((char) c);
				} while (!Character.isWhitespace(c = System.in.read()));
				return res.toString();
			} catch (Exception e) {
				return null;
			}
		}
		String nextLine(){
			try{
				StringBuilder res =new StringBuilder("");
				int c = System.in.read();
				while (c=='\r' || c=='\n')
					c = System.in.read();
				do {
					res.append((char) c);
					c = System.in.read();
				} while (c!='\r' && c!='\n');
				return res.toString();
			}catch (Exception e) {
				return null;
			}
		}
	}

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

Submission Info

Judge Result