結果

問題 No.827 総神童数
ユーザー kusomushikusomushi
提出日時 2019-07-08 20:43:32
言語 Java21
(openjdk 21)
結果
AC  
実行時間 615 ms / 2,000 ms
コード長 7,150 bytes
コンパイル時間 2,745 ms
コンパイル使用メモリ 79,496 KB
実行使用メモリ 61,144 KB
最終ジャッジ日時 2024-04-17 18:42:32
合計ジャッジ時間 16,044 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
このコードへのチャレンジ
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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 44 ms
37,312 KB
testcase_01 AC 47 ms
37,332 KB
testcase_02 AC 45 ms
37,088 KB
testcase_03 AC 46 ms
37,432 KB
testcase_04 AC 45 ms
37,488 KB
testcase_05 AC 44 ms
37,244 KB
testcase_06 AC 44 ms
37,464 KB
testcase_07 AC 44 ms
37,256 KB
testcase_08 AC 44 ms
37,028 KB
testcase_09 AC 592 ms
60,044 KB
testcase_10 AC 308 ms
50,904 KB
testcase_11 AC 102 ms
40,012 KB
testcase_12 AC 211 ms
47,360 KB
testcase_13 AC 510 ms
59,552 KB
testcase_14 AC 128 ms
41,320 KB
testcase_15 AC 327 ms
47,796 KB
testcase_16 AC 519 ms
59,084 KB
testcase_17 AC 586 ms
60,828 KB
testcase_18 AC 347 ms
47,148 KB
testcase_19 AC 603 ms
60,824 KB
testcase_20 AC 491 ms
58,536 KB
testcase_21 AC 388 ms
52,104 KB
testcase_22 AC 505 ms
59,816 KB
testcase_23 AC 86 ms
39,008 KB
testcase_24 AC 566 ms
60,352 KB
testcase_25 AC 512 ms
57,460 KB
testcase_26 AC 570 ms
59,312 KB
testcase_27 AC 406 ms
55,936 KB
testcase_28 AC 401 ms
53,760 KB
testcase_29 AC 365 ms
49,868 KB
testcase_30 AC 202 ms
46,344 KB
testcase_31 AC 335 ms
49,580 KB
testcase_32 AC 325 ms
46,612 KB
testcase_33 AC 584 ms
59,980 KB
testcase_34 AC 549 ms
60,124 KB
testcase_35 AC 330 ms
50,032 KB
testcase_36 AC 394 ms
55,204 KB
testcase_37 AC 442 ms
57,252 KB
testcase_38 AC 615 ms
61,144 KB
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ソースコード

diff # 

import java.io.*;
import java.util.Arrays;
import java.util.StringJoiner;
import java.util.StringTokenizer;

public class Main {

    static int N;
    static int[] A, B;

    public static void main(String[] args) {
        FastScanner sc = new FastScanner(System.in);
        N = sc.nextInt();
        A = new int[N-1];
        B = new int[N-1];
        for (int i = 0; i < N - 1; i++) {
            A[i] = sc.nextInt()-1;
            B[i] = sc.nextInt()-1;
        }

        System.out.println(solve());
    }
    
    static int solve() {
        int[][] G = adjB(N, A, B);
        int[] dist = new int[N];
        for (Node node : order(N, G, 0, true)) {
            for (int b : G[node.a]) {
                if( b == node.parent ) continue;
                dist[b] = dist[node.a] + 1;
            }
        }

        int nFact = 1;
        for (int i = 2; i <= N; i++) {
            nFact = mul(i, nFact);
        }

        int ans = 0;
        for (int i = 0; i < N; i++) {
            int d = dist[i];
            // N! / (d+1)
            ans += div(nFact, d+1);
            ans %= MOD;
        }
        return ans;
    }

    static int MOD = 1_000_000_007;

    static int pow(int base, long exp) {
        if( exp == 0 ) return 1;

        int ans = 1;
        base %= MOD;
        while( exp > 0 ) {
            if( (exp & 1) == 1 ) {
                ans = mul(ans, base);
            }

            base = mul(base, base);
            exp = exp >> 1;
        }
        return ans;
    }

    static int sub(int a, int b) {
        int c = a - b;
        if( c < 0 ) c += MOD;
        return c;
    }

    static int div(int a, int b) {
        return mul(a, pow(b, MOD-2));
    }

    static int add(int a, int b) {
        int c = a + b;
        if( c >= MOD ) c %= MOD;
        return c;
    }

    static int mul(int a, int b) {
        long c = (long)a * b;
        if( c >= MOD ) c %= MOD;
        return (int)c;
    }
    
    static class Node {
        int parent, a;

        public Node(int parent, int a) {
            this.parent = parent;
            this.a = a;
        }
    }

    static Node[] order(int N, int[][] G, int root, boolean fromRoot) {
        Node[] q = new Node[N];
        int u = 0, v = 0;
        Node[] ret = new Node[N];
        int idx = fromRoot ? 0 : N-1;
        int d = fromRoot ? 1 : -1;
        q[v++] = new Node(-1, root);
        while( u != v ) {
            Node n = q[u++];
            ret[idx] = n;
            idx += d;
            for (int b : G[n.a]) {
                if( b == n.parent ) continue;

                q[v++] = new Node(n.a, b);
            }
        }
        return ret;
    }

    static int[][] adjB(int n, int[] from, int[] to) {
        int[][] adj = new int[n][];
        int[] cnt = new int[n];
        for (int f : from) {
            cnt[f]++;
        }
        for (int t : to) {
            cnt[t]++;
        }
        for (int i = 0; i < n; i++) {
            adj[i] = new int[cnt[i]];
        }
        for (int i = 0; i < from.length; i++) {
            adj[from[i]][--cnt[from[i]]] = to[i];
            adj[to[i]][--cnt[to[i]]] = from[i];
        }
        return adj;
    }

    @SuppressWarnings("unused")
    static class FastScanner {
        private BufferedReader reader;
        private StringTokenizer tokenizer;

        FastScanner(InputStream in) {
            reader = new BufferedReader(new InputStreamReader(in));
            tokenizer = null;
        }

        String next() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        String nextLine() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    return reader.readLine();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken("\n");
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        int[] nextIntArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++) a[i] = nextInt();
            return a;
        }

        int[] nextIntArray(int n, int delta) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++) a[i] = nextInt() + delta;
            return a;
        }

        long[] nextLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++) a[i] = nextLong();
            return a;
        }
    }

    static void writeLines(int[] as) {
        PrintWriter pw = new PrintWriter(System.out);
        for (int a : as) pw.println(a);
        pw.flush();
    }

    static void writeLines(long[] as) {
        PrintWriter pw = new PrintWriter(System.out);
        for (long a : as) pw.println(a);
        pw.flush();
    }

    static void writeSingleLine(int[] as) {
        PrintWriter pw = new PrintWriter(System.out);
        for (int i = 0; i < as.length; i++) {
            if (i != 0) pw.print(" ");
            pw.print(as[i]);
        }
        pw.println();
        pw.flush();
    }

    static int max(int... as) {
        int max = Integer.MIN_VALUE;
        for (int a : as) max = Math.max(a, max);
        return max;
    }

    static int min(int... as) {
        int min = Integer.MAX_VALUE;
        for (int a : as) min = Math.min(a, min);
        return min;
    }

    static void debug(Object... args) {
        StringJoiner j = new StringJoiner(" ");
        for (Object arg : args) {
            if (arg == null) j.add("null");
            else if (arg instanceof int[]) j.add(Arrays.toString((int[]) arg));
            else if (arg instanceof long[]) j.add(Arrays.toString((long[]) arg));
            else if (arg instanceof double[]) j.add(Arrays.toString((double[]) arg));
            else if (arg instanceof Object[]) j.add(Arrays.toString((Object[]) arg));
            else j.add(arg.toString());
        }
        System.err.println(j.toString());
    }

    static void printSingleLine(int[] array) {
        PrintWriter pw = new PrintWriter(System.out);
        for (int i = 0; i < array.length; i++) {
            if (i != 0) pw.print(" ");
            pw.print(array[i]);
        }
        pw.println();
        pw.flush();
    }

    static int lowerBound(int[] array, int value) {
        int lo = 0, hi = array.length, mid;
        while (lo < hi) {
            mid = (hi + lo) / 2;
            if (array[mid] < value) lo = mid + 1;
            else hi = mid;
        }
        return lo;
    }

    static int upperBound(int[] array, int value) {
        int lo = 0, hi = array.length, mid;
        while (lo < hi) {
            mid = (hi + lo) / 2;
            if (array[mid] <= value) lo = mid + 1;
            else hi = mid;
        }
        return lo;
    }
}
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