結果

問題 No.827 総神童数
ユーザー OlandOland
提出日時 2019-05-24 02:33:34
言語 Java21
(openjdk 21)
結果
AC  
実行時間 629 ms / 2,000 ms
コード長 5,298 bytes
コンパイル時間 3,068 ms
コンパイル使用メモリ 80,672 KB
実行使用メモリ 108,604 KB
最終ジャッジ日時 2023-10-17 11:46:38
合計ジャッジ時間 22,206 ms
ジャッジサーバーID
（参考情報） 		judge12 / judge13
このコードへのチャレンジ（β）

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 108 ms
63,052 KB
testcase_01 AC 110 ms
63,004 KB
testcase_02 AC 108 ms
63,040 KB
testcase_03 AC 109 ms
63,016 KB
testcase_04 AC 105 ms
62,976 KB
testcase_05 AC 108 ms
63,028 KB
testcase_06 AC 107 ms
63,024 KB
testcase_07 AC 110 ms
63,040 KB
testcase_08 AC 110 ms
63,024 KB
testcase_09 AC 596 ms
108,604 KB
testcase_10 AC 338 ms
80,804 KB
testcase_11 AC 149 ms
64,840 KB
testcase_12 AC 232 ms
70,568 KB
testcase_13 AC 472 ms
89,440 KB
testcase_14 AC 174 ms
65,396 KB
testcase_15 AC 311 ms
78,600 KB
testcase_16 AC 492 ms
104,220 KB
testcase_17 AC 540 ms
108,444 KB
testcase_18 AC 345 ms
81,952 KB
testcase_19 AC 598 ms
108,472 KB
testcase_20 AC 492 ms
100,248 KB
testcase_21 AC 422 ms
85,252 KB
testcase_22 AC 555 ms
104,368 KB
testcase_23 AC 126 ms
61,956 KB
testcase_24 AC 570 ms
104,356 KB
testcase_25 AC 481 ms
100,292 KB
testcase_26 AC 570 ms
104,500 KB
testcase_27 AC 446 ms
85,944 KB
testcase_28 AC 437 ms
96,244 KB
testcase_29 AC 418 ms
82,116 KB
testcase_30 AC 247 ms
70,304 KB
testcase_31 AC 356 ms
79,640 KB
testcase_32 AC 369 ms
80,980 KB
testcase_33 AC 629 ms
108,312 KB
testcase_34 AC 595 ms
104,396 KB
testcase_35 AC 379 ms
81,452 KB
testcase_36 AC 441 ms
84,956 KB
testcase_37 AC 489 ms
100,288 KB
testcase_38 AC 618 ms
108,436 KB
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ソースコード

diff # 

import java.io.*;
import java.util.*;
import java.util.Map.Entry;

@SuppressWarnings("unused")
public class Main {
	
	//final boolean isDebug = true;
	final boolean isDebug = false;
	String fileName = "input.txt";
	FastScanner sc;
	PrintWriter out;
	final int MOD = (int)1e9+7;
	//final int INF = Integer.MAX_VALUE / 2;
	final long INF = Long.MAX_VALUE / 2;
	
	//任意の頂点における、祖先がk個のときの神童数の和
	long[] calcA;
	long[] sumP;
	
	void solve() throws Exception{
		int N = sc.nextInt();
		ArrayList<ArrayList<Integer>> G = new ArrayList<>();
		for(int i = 0; i < N; i++) G.add(new ArrayList<>());
		for(int i = 0; i < N-1; i++){
			int u = sc.nextInt()-1, v = sc.nextInt()-1;
			G.get(u).add(v); G.get(v).add(u);
		}
		
		int[] numA = new int[N];
		Arrays.fill(numA, Integer.MAX_VALUE);
		numA[0] = 0;
		Deque<Integer> dequeue = new ArrayDeque<Integer>();
		dequeue.addLast(0);
		
		CombCalculator cc = new CombCalculator();
		long ans = cc.fact(N);
		
		while(!dequeue.isEmpty()){
			int now = dequeue.removeFirst();
			for(int next : G.get(now)){
				if(numA[next] > numA[now] + 1){
					numA[next] = numA[now] + 1;
					ans = (ans + (cc.fact(N) * cc.inv(numA[next] + 1)) % MOD) % MOD;
					dequeue.add(next);
				}
			}
		}
		System.out.println(ans);
 	}
	
	/* end solve */
	
	/* main */
	public static void main(String[] args) throws Exception {
		new Main().m();
	}
	
	void m() throws Exception {
		long S = System.currentTimeMillis();
		sc = (isDebug) ? new FastScanner(new FileInputStream(fileName)) : new FastScanner(System.in);
		out = new PrintWriter(System.out);
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		if(isDebug){
			System.out.println("---Debug---");
			System.out.printf("%8d ms\n", (G-S));
		}
	}
	/* end main */
}
/* end Main */

class CombCalculator{
	//引数の最大値、MOD、階乗・MODの逆元・階乗の逆元のテーブル
	static int MAX_FAC = 510000;
	static int MOD = (int)1e9+7;
	static long[] fac = new long[MAX_FAC+1];
	static long[] finv = new long[MAX_FAC+1];
	static long[] inv = new long[MAX_FAC+1];
	
	public CombCalculator(){
		initComb();
	}
	
	//テーブルの初期化
	void initComb(){
		fac[0] = finv[0] = inv[0] = fac[1] = finv[1] = inv[1] = 1;
		for (int i = 2; i <= MAX_FAC; ++i) {
			fac[i] = fac[i - 1] * i % MOD;
			inv[i] = MOD - (MOD / i) * inv[(int) (MOD % i)] % MOD;
			finv[i] = finv[i - 1] * inv[i] % MOD;
		}
	}
	
	//nPk % MOD
	public long perm(int n, int k){
		return fac[n] * finv[n - k] % MOD;
	}
	
	//nCk % MOD
	public long comb(int n, int k){
		return fac[n] * finv[k] % MOD * finv[n - k] % MOD;
	}
	
	//n! % MOD
	public long fact(int n){
		return fac[n];
	}
	
	//(n!)^-1 % MOD
	public long factInv(int n){
		return finv[n];
	}
	
	//n^-1 % MOD
	public long inv(int n){
		return inv[n];
	}
}

class FastScanner {
    private InputStream in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    public FastScanner(InputStream in) {
		this.in = in;
	}
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() {
    	if (hasNextByte()) return buffer[ptr++];
    	else return -1;
    }
    private static boolean isPrintableChar(int c){
    	return 33 <= c && c <= 126;
    }
    public boolean hasNext() {
    	while(hasNextByte() && !isPrintableChar(buffer[ptr]))
    		ptr++; return hasNextByte();
    }
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public String nextLine() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(b != 10) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() {
    	return Double.parseDouble(next());
    }
}
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