結果
問題 | No.758 VVVVV |
ユーザー |
|
提出日時 | 2018-12-06 00:15:59 |
言語 | Java (openjdk 23) |
結果 |
AC
|
実行時間 | 166 ms / 2,000 ms |
コード長 | 5,539 bytes |
コンパイル時間 | 4,417 ms |
コンパイル使用メモリ | 85,068 KB |
実行使用メモリ | 47,048 KB |
最終ジャッジ日時 | 2024-10-14 01:46:10 |
合計ジャッジ時間 | 8,020 ms |
ジャッジサーバーID (参考情報) |
judge5 / judge3 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 23 |
ソースコード
package adv2018;import java.io.ByteArrayInputStream;import java.io.IOException;import java.io.InputStream;import java.io.PrintWriter;import java.util.Arrays;import java.util.InputMismatchException;public class Day6 {InputStream is;PrintWriter out;String INPUT = "";void solve(){int n = ni();int[] from = new int[n - 1];int[] to = new int[n - 1];for (int i = 0; i < n - 1; i++) {from[i] = ni() - 1;to[i] = ni() - 1;}int[][] g = packU(n, from, to);int mod = 1000000007;int[][] fif = enumFIF(100005, mod);if(n == 1) {out.println(1);return;}int m = 0;for(int i = 1;i < n;i++) {if(g[i].length == 1)m++;}// m = 2*m-1;// n = 2*n-2;n--;out.println(C(n-1, m-1, mod, fif) * C(n, m-1, mod, fif) % mod * invl(m, mod) % mod);//// 1 3 1// 1 6 6 1// int n = 4*2-2;// int mod = 1000000007;// int m = 5;// long[][][][] dp = new long[n+1][m+1][100][2];// dp[0][0][0][0] = 1;//// for(int i = 0;i < n;i++) {// for(int j = 0;j <= m;j++) {// for(int h = 0;h < 100;h++) {// for(int p = 0;p < 2;p++) {// for(int q = 0;q < 2;q++) {// int nh = h+(q == 0 ? 1 : -1);// if(nh >= 100 || nh < 0)continue;// if(p == q) {// dp[i+1][j][nh][q] += dp[i][j][h][p];// }else {// if(j+1 <= m) {// dp[i+1][j+1][nh][q] += dp[i][j][h][p];// }// }// }// }// }// }// }// tr(dp[n][m][0][0] + dp[n][m][0][1]);}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 int[][] enumFIF(int n, int mod) {int[] f = new int[n + 1];int[] invf = new int[n + 1];f[0] = 1;for (int i = 1; i <= n; i++) {f[i] = (int) ((long) f[i - 1] * i % mod);}long a = f[n];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;}invf[n] = (int) (p < 0 ? p + mod : p);for (int i = n - 1; i >= 0; i--) {invf[i] = (int) ((long) invf[i + 1] * (i + 1) % mod);}return new int[][] { f, invf };}public static long C(int n, int r, int mod, int[][] fif) {if (n < 0 || r < 0 || r > n)return 0;return (long) fif[0][n] * fif[1][r] % mod * fif[1][n - r] % mod;}static int[][] packU(int n, int[] from, int[] to) {int[][] g = new int[n][];int[] p = new int[n];for (int f : from)p[f]++;for (int t : to)p[t]++;for (int i = 0; i < n; i++)g[i] = new int[p[i]];for (int i = 0; i < from.length; i++) {g[from[i]][--p[from[i]]] = to[i];g[to[i]][--p[to[i]]] = from[i];}return g;}void run() throws Exception{is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());out = new PrintWriter(System.out);long s = System.currentTimeMillis();solve();out.flush();if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");// Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){// @Override// public void run() {// long s = System.currentTimeMillis();// solve();// out.flush();// if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");// }// };// t.start();// t.join();}public static void main(String[] args) throws Exception { new Day6().run(); }private byte[] inbuf = new byte[1024];public int lenbuf = 0, ptrbuf = 0;private int readByte(){if(lenbuf == -1)throw new InputMismatchException();if(ptrbuf >= lenbuf){ptrbuf = 0;try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }if(lenbuf <= 0)return -1;}return inbuf[ptrbuf++];}private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }private double nd() { return Double.parseDouble(ns()); }private char nc() { return (char)skip(); }private String ns(){int b = skip();StringBuilder sb = new StringBuilder();while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')sb.appendCodePoint(b);b = readByte();}return sb.toString();}private char[] ns(int n){char[] buf = new char[n];int b = skip(), p = 0;while(p < n && !(isSpaceChar(b))){buf[p++] = (char)b;b = readByte();}return n == p ? buf : Arrays.copyOf(buf, p);}private int[] na(int n){int[] a = new int[n];for(int i = 0;i < n;i++)a[i] = ni();return a;}private long[] nal(int n){long[] a = new long[n];for(int i = 0;i < n;i++)a[i] = nl();return a;}private char[][] nm(int n, int m) {char[][] map = new char[n][];for(int i = 0;i < n;i++)map[i] = ns(m);return map;}private int[][] nmi(int n, int m) {int[][] map = new int[n][];for(int i = 0;i < n;i++)map[i] = na(m);return map;}private int ni() { return (int)nl(); }private long nl(){long num = 0;int b;boolean minus = false;while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));if(b == '-'){minus = true;b = readByte();}while(true){if(b >= '0' && b <= '9'){num = num * 10 + (b - '0');}else{return minus ? -num : num;}b = readByte();}}private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }}