結果

問題 No.1507 Road Blocked
ユーザー shojin_proshojin_pro
提出日時 2021-05-14 23:24:06
言語 Java17
(openjdk 17.0.1)
結果
AC  
実行時間 555 ms / 2,000 ms
コード長 4,715 bytes
コンパイル時間 1,972 ms
使用メモリ 78,780 KB
最終ジャッジ日時 2022-11-25 22:35:26
合計ジャッジ時間 19,980 ms
ジャッジサーバーID
（参考情報） 		judge14 / judge15
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
使用メモリ
testcase_00 AC 56 ms
38,732 KB
testcase_01 AC 57 ms
38,804 KB
testcase_02 AC 54 ms
38,968 KB
testcase_03 AC 550 ms
78,780 KB
testcase_04 AC 499 ms
59,472 KB
testcase_05 AC 502 ms
61,276 KB
testcase_06 AC 464 ms
60,892 KB
testcase_07 AC 525 ms
60,860 KB
testcase_08 AC 488 ms
61,028 KB
testcase_09 AC 493 ms
60,964 KB
testcase_10 AC 458 ms
60,096 KB
testcase_11 AC 512 ms
62,368 KB
testcase_12 AC 555 ms
60,840 KB
testcase_13 AC 491 ms
60,812 KB
testcase_14 AC 507 ms
62,292 KB
testcase_15 AC 465 ms
60,984 KB
testcase_16 AC 495 ms
61,260 KB
testcase_17 AC 472 ms
61,124 KB
testcase_18 AC 453 ms
61,080 KB
testcase_19 AC 515 ms
60,816 KB
testcase_20 AC 471 ms
60,688 KB
testcase_21 AC 460 ms
60,672 KB
testcase_22 AC 475 ms
60,992 KB
testcase_23 AC 484 ms
62,168 KB
testcase_24 AC 499 ms
61,308 KB
testcase_25 AC 528 ms
60,936 KB
testcase_26 AC 473 ms
60,960 KB
testcase_27 AC 477 ms
61,076 KB
testcase_28 AC 458 ms
60,892 KB
testcase_29 AC 466 ms
61,976 KB
testcase_30 AC 510 ms
61,256 KB
testcase_31 AC 509 ms
61,088 KB
testcase_32 AC 479 ms
62,372 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

import java.util.*;
import java.io.*;

public class Main {
    static FastScanner sc = new FastScanner(System.in);
    static PrintWriter pw = new PrintWriter(System.out);
    static StringBuilder sb = new StringBuilder();
    static long mod = (long) 998244353;
    
    static int N;
    static int[] A = new int[1 << 18], B = new int[1 << 18];
    static long[] dp = new long[1 << 18];
    static ArrayList<ArrayList<Integer>> G = new ArrayList<>();
    
    static void dfs(int pos, int pre) {
    	dp[pos] = 1;
    	for (int i : G.get(pos)) {
    		if (i == pre) continue;
    		dfs(i, pos);
    		dp[pos] += dp[i];
    	}
    }

    public static void main(String[] args) throws Exception {
        solve();
        pw.flush();
    }

    public static void solve() {
    	N = sc.nextInt();
    	for(int i = 0; i < N; i++) G.add(new ArrayList<>());
    	for (int i = 0; i < N - 1; i++) {
    		A[i] = sc.nextInt()-1; B[i] = sc.nextInt()-1;
    		G.get(A[i]).add(B[i]);
    		G.get(B[i]).add(A[i]);
    	}
    
    	dfs(1, -1);
    
    	long num = 0;
    	for (int i = 0; i < N-1; i++) {
    		long r = Math.min(dp[A[i]], dp[B[i]]);
    		num += r * (long)(N - r);
    	}
    	long deno = 1L*(long)N*(long)(N-1)/2L*(long)(N-1);
    	num = (deno-num);
    	long gcd = gcd(num,deno);
    	num /= gcd; deno /= gcd;
    	num %= mod; deno %= mod;
    	long ans = rep2(deno,mod-2,mod);
    	num *= ans;
    	num %= mod;
    	pw.println(num);
    }
    
    private static long gcd(long a, long b)
    {
        while (b > 0)
        {
            long temp = b;
            b = a % b; // % is remainder
            a = temp;
        }
        return a;
    }
    
    private static long rep2(long b, long n, long mod){
        if(n == 0) return 1;
        long bn = rep2(b,n/2,mod);
        if(n % 2 == 0){
            return (bn*bn)%mod;
        }else{
            return (bn*bn)%mod*b%mod;
        }
    }

    static class GeekInteger {
        public static void save_sort(int[] array) {
            shuffle(array);
            Arrays.sort(array);
        }

        public static int[] shuffle(int[] array) {
            int n = array.length;
            Random random = new Random();
            for (int i = 0, j; i < n; i++) {
                j = i + random.nextInt(n - i);
                int randomElement = array[j];
                array[j] = array[i];
                array[i] = randomElement;
            }
            return array;
        }

        public static void save_sort(long[] array) {
            shuffle(array);
            Arrays.sort(array);
        }

        public static long[] shuffle(long[] array) {
            int n = array.length;
            Random random = new Random();
            for (int i = 0, j; i < n; i++) {
                j = i + random.nextInt(n - i);
                long randomElement = array[j];
                array[j] = array[i];
                array[i] = randomElement;
            }
            return array;
        }

    }
}

class FastScanner {
    private BufferedReader reader = null;
    private StringTokenizer tokenizer = null;

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

    public FastScanner(FileReader in) {
        reader = new BufferedReader(in);
        tokenizer = null;
    }

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

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

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

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

    public double nextDouble() {
        return Double.parseDouble(next());
    }

    public String[] nextArray(int n) {
        String[] a = new String[n];
        for (int i = 0; i < n; i++)
            a[i] = next();
        return a;
    }

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

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