結果
問題 | No.758 VVVVV |
ユーザー | hiromi_ayase |
提出日時 | 2018-12-07 13:50:53 |
言語 | Java21 (openjdk 21) |
結果 |
AC
|
実行時間 | 260 ms / 2,000 ms |
コード長 | 3,417 bytes |
コンパイル時間 | 2,513 ms |
コンパイル使用メモリ | 81,996 KB |
実行使用メモリ | 47,468 KB |
最終ジャッジ日時 | 2024-04-22 03:00:32 |
合計ジャッジ時間 | 7,993 ms |
ジャッジサーバーID (参考情報) |
judge3 / judge1 |
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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 | 69 ms
37,820 KB |
testcase_01 | AC | 68 ms
38,180 KB |
testcase_02 | AC | 67 ms
38,236 KB |
testcase_03 | AC | 251 ms
47,292 KB |
testcase_04 | AC | 202 ms
45,164 KB |
testcase_05 | AC | 177 ms
44,740 KB |
testcase_06 | AC | 175 ms
43,956 KB |
testcase_07 | AC | 244 ms
47,276 KB |
testcase_08 | AC | 200 ms
46,988 KB |
testcase_09 | AC | 157 ms
44,712 KB |
testcase_10 | AC | 182 ms
44,948 KB |
testcase_11 | AC | 251 ms
47,468 KB |
testcase_12 | AC | 167 ms
45,472 KB |
testcase_13 | AC | 173 ms
44,072 KB |
testcase_14 | AC | 156 ms
44,356 KB |
testcase_15 | AC | 149 ms
42,160 KB |
testcase_16 | AC | 150 ms
43,288 KB |
testcase_17 | AC | 250 ms
47,180 KB |
testcase_18 | AC | 195 ms
45,228 KB |
testcase_19 | AC | 245 ms
47,180 KB |
testcase_20 | AC | 171 ms
44,600 KB |
testcase_21 | AC | 182 ms
44,148 KB |
testcase_22 | AC | 260 ms
47,444 KB |
testcase_23 | AC | 67 ms
38,168 KB |
testcase_24 | AC | 68 ms
38,300 KB |
testcase_25 | AC | 70 ms
38,076 KB |
ソースコード
public class Main { private static void solve() { int n = ni(); if (n == 1) { System.out.println(1); return; } int[] cnt = new int[n]; for (int i = 0; i < n-1; i ++) { cnt[ni() - 1] ++; cnt[ni() - 1] ++; } int leaf = 0; for (int i = 1; i < n; i ++) { if (cnt[i] == 1) leaf ++; } int mod = 1000000000 + 7; long ret = c(n - 1, leaf - 1, mod) * c(n - 2, leaf - 1, mod) % mod; ret = ret * invl(leaf, mod) % mod; System.out.println(ret); } private static long c(int n, int r, int mod) { long x = 1; long y = 1; for (int i = 0; i < r; i ++) { x *= n - i; y *= i + 1; x %= mod; y %= mod; } return x * invl(y, mod) % mod; } public static long invl(long a, long mod) { long b = mod; long p = 1, q = 0; while (b > 0) { long c = a / b; long d; d = a; a = b; b = d % b; d = p; p = q; q = d - c * q; } return p < 0 ? p + mod : p; } public static void main(String[] args) { new Thread(null, new Runnable() { @Override public void run() { long start = System.currentTimeMillis(); String debug = args.length > 0 ? args[0] : null; if (debug != null) { try { is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug)); } catch (Exception e) { throw new RuntimeException(e); } } reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768); solve(); out.flush(); tr((System.currentTimeMillis() - start) + "ms"); } }, "", 64000000).start(); } private static java.io.InputStream is = System.in; private static java.io.PrintWriter out = new java.io.PrintWriter(System.out); private static java.util.StringTokenizer tokenizer = null; private static java.io.BufferedReader reader; public static String next() { while (tokenizer == null || !tokenizer.hasMoreTokens()) { try { tokenizer = new java.util.StringTokenizer(reader.readLine()); } catch (Exception e) { throw new RuntimeException(e); } } return tokenizer.nextToken(); } private static double nd() { return Double.parseDouble(next()); } private static long nl() { return Long.parseLong(next()); } private static int[] na(int n) { int[] a = new int[n]; for (int i = 0; i < n; i++) a[i] = ni(); return a; } private static char[] ns() { return next().toCharArray(); } private static long[] nal(int n) { long[] a = new long[n]; for (int i = 0; i < n; i++) a[i] = nl(); return a; } private static int[][] ntable(int n, int m) { int[][] table = new int[n][m]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { table[i][j] = ni(); } } return table; } private static int[][] nlist(int n, int m) { int[][] table = new int[m][n]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { table[j][i] = ni(); } } return table; } private static int ni() { return Integer.parseInt(next()); } private static void tr(Object... o) { if (is != System.in) System.out.println(java.util.Arrays.deepToString(o)); } }