結果

問題 No.1103 Directed Length Sum
ユーザー shojin_proshojin_pro
提出日時 2020-07-03 23:06:59
言語 Java19
(openjdk 21)
結果
AC  
実行時間 1,011 ms / 3,000 ms
コード長 2,698 bytes
コンパイル時間 2,254 ms
コンパイル使用メモリ 77,708 KB
実行使用メモリ 84,912 KB
最終ジャッジ日時 2023-10-17 06:08:11
合計ジャッジ時間 16,444 ms
ジャッジサーバーID
(参考情報)
judge15 / 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 52 ms
53,488 KB
testcase_01 AC 52 ms
53,480 KB
testcase_02 AC 873 ms
84,912 KB
testcase_03 AC 570 ms
75,480 KB
testcase_04 AC 932 ms
77,852 KB
testcase_05 AC 735 ms
78,544 KB
testcase_06 AC 522 ms
65,540 KB
testcase_07 AC 255 ms
57,956 KB
testcase_08 AC 315 ms
60,464 KB
testcase_09 AC 219 ms
58,448 KB
testcase_10 AC 392 ms
68,364 KB
testcase_11 AC 908 ms
77,704 KB
testcase_12 AC 634 ms
75,476 KB
testcase_13 AC 373 ms
63,956 KB
testcase_14 AC 189 ms
58,252 KB
testcase_15 AC 517 ms
71,580 KB
testcase_16 AC 684 ms
72,932 KB
testcase_17 AC 1,011 ms
79,508 KB
testcase_18 AC 368 ms
63,980 KB
testcase_19 AC 885 ms
77,796 KB
testcase_20 AC 232 ms
58,384 KB
testcase_21 AC 296 ms
61,200 KB
testcase_22 AC 840 ms
77,476 KB
testcase_23 AC 582 ms
67,064 KB
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ソースコード

diff #

import java.util.*;
import java.io.*;
 
public class Main {
    static boolean[] arrived;
    static long[] cum;
    public static void main(String[] args) throws Exception {
        long mod = (long)Math.pow(10,9)+7;
        FastScanner sc = new FastScanner(System.in);
        int n = sc.nextInt();
        int[] from = new int[n+1];
        cum = new long[n+1];
        for(int i = 1; i <= n; i++){
            cum[i] += cum[i-1]+i;
        }
        for(int i = 0; i < n-1; i++){
            int a = sc.nextInt();
            int b = sc.nextInt();
            from[b] = a;
        }
        long ans = 0;
        long[] step = new long[n+1];
        for(int i = 1; i <= n; i++){
            int cnt = 0;
            int now = i;
            while(from[now] != 0){
                if(now < i){
                    cnt += step[now];
                    break;
                }
                now = from[now];
                cnt++;
            }
            ans += cum[cnt];
            ans %= mod;
            step[i] = cnt;
        }
        System.out.println(ans);
    }
}

class FastScanner {
    private BufferedReader reader = null;
    private StringTokenizer tokenizer = null;
    public FastScanner(InputStream in) {
        reader = new BufferedReader(new InputStreamReader(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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