提出 #56874675

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ソースコード 拡げる

import static java.lang.Integer.parseInt;
import static java.lang.Long.parseLong;
import static java.lang.System.exit;
import static java.util.Arrays.fill;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {

	static boolean e[][];
	static int c[];

	static void solve() throws Exception {
		int tests = scanInt();
		test: for (int test = 0; test < tests; test++) {
			int n = scanInt(), m = scanInt(), a[] = new int[m], b[] = new int[m];
			for (int i = 0; i < m; i++) {
				a[i] = scanInt() - 1;
				b[i] = scanInt() - 1;
			}
			if (m < (long) n * (n - 1) / 2 - (long) (n / 2) * ((n + 1) / 2)) {
				out.println("No");
				continue;
			}
			e = new boolean[n][n];
			for (int i = 0; i < n; i++) {
				fill(e[i], true);
				e[i][i] = false;
			}
			for (int i = 0; i < m; i++) {
				e[a[i]][b[i]] = e[b[i]][a[i]] = false;
			}
			c = new int[n];
			for (int i = 0; i < n; i++) {
				if (c[i] == 0) {
					if (!dfs(i, 1)) {
						out.println("No");
						continue test;
					}
				}
			}
			out.println("Yes");
		}
	}

	static boolean dfs(int cur, int col) {
		c[cur] = col;
		for (int next = 0; next < e.length; next++) {
			if (e[cur][next]) {
				if (c[next] == 0) {
					if (!dfs(next, -col)) {
						return false;
					}
				} else if (c[next] != -col) {
					return false;
				}
			}
		}
		return true;
	}

	static int scanInt() throws IOException {
		return parseInt(scanString());
	}

	static long scanLong() throws IOException {
		return parseLong(scanString());
	}

	static String scanString() throws IOException {
		while (tok == null || !tok.hasMoreTokens()) {
			tok = new StringTokenizer(in.readLine());
		}
		return tok.nextToken();
	}

	static BufferedReader in;
	static PrintWriter out;
	static StringTokenizer tok;

	public static void main(String[] args) {
		try {
			in = new BufferedReader(new InputStreamReader(System.in));
			out = new PrintWriter(System.out);
			solve();
			in.close();
			out.close();
		} catch (Throwable e) {
			e.printStackTrace();
			exit(1);
		}
	}
}

提出情報

ジャッジ結果