結果

問題 No.196 典型DP (1)
ユーザー uwiuwi
提出日時 2015-04-26 22:41:15
言語 Java21
(openjdk 21)
結果
AC  
実行時間 149 ms / 2,000 ms
コード長 4,779 bytes
コンパイル時間 5,997 ms
コンパイル使用メモリ 76,952 KB
実行使用メモリ 57,136 KB
最終ジャッジ日時 2023-09-18 12:14:10
合計ジャッジ時間 11,007 ms
ジャッジサーバーID
（参考情報） 		judge14 / judge11
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 39 ms
33,640 KB
testcase_01 AC 38 ms
33,684 KB
testcase_02 AC 39 ms
33,492 KB
testcase_03 AC 38 ms
33,276 KB
testcase_04 AC 39 ms
33,380 KB
testcase_05 AC 38 ms
33,408 KB
testcase_06 AC 39 ms
33,456 KB
testcase_07 AC 38 ms
33,648 KB
testcase_08 AC 39 ms
33,384 KB
testcase_09 AC 39 ms
33,540 KB
testcase_10 AC 39 ms
33,864 KB
testcase_11 AC 39 ms
33,636 KB
testcase_12 AC 40 ms
33,492 KB
testcase_13 AC 39 ms
33,480 KB
testcase_14 AC 39 ms
33,300 KB
testcase_15 AC 44 ms
33,568 KB
testcase_16 AC 55 ms
34,176 KB
testcase_17 AC 83 ms
35,840 KB
testcase_18 AC 108 ms
37,316 KB
testcase_19 AC 104 ms
37,276 KB
testcase_20 AC 113 ms
37,212 KB
testcase_21 AC 119 ms
38,344 KB
testcase_22 AC 113 ms
37,624 KB
testcase_23 AC 124 ms
45,772 KB
testcase_24 AC 123 ms
43,792 KB
testcase_25 AC 121 ms
43,908 KB
testcase_26 AC 137 ms
56,796 KB
testcase_27 AC 136 ms
56,796 KB
testcase_28 AC 136 ms
57,136 KB
testcase_29 AC 135 ms
57,124 KB
testcase_30 AC 138 ms
56,716 KB
testcase_31 AC 124 ms
39,996 KB
testcase_32 AC 143 ms
39,848 KB
testcase_33 AC 143 ms
39,916 KB
testcase_34 AC 141 ms
39,996 KB
testcase_35 AC 142 ms
39,864 KB
testcase_36 AC 149 ms
40,256 KB
testcase_37 AC 116 ms
38,092 KB
testcase_38 AC 141 ms
55,204 KB
testcase_39 AC 135 ms
55,136 KB
testcase_40 AC 147 ms
55,016 KB
testcase_41 AC 44 ms
48,980 KB
testcase_42 AC 44 ms
49,312 KB
testcase_43 AC 44 ms
49,140 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 # 

package contest;

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 Q234 {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni(), K = ni();
		int[] from = new int[n-1];
		int[] to = new int[n-1];
		for(int i = 0;i < n-1;i++){
			from[i] = ni();
			to[i] = ni();
		}
		int[][] g = packU(n, from, to);
		int[][] pars = parents3(g, 0);
		int[] par = pars[0], ord = pars[1];
		int mod = 1000000007;
		long[][] dp = new long[n][];
		int[] des = new int[n];
		for(int i = n-1;i >= 0;i--){
			int cur = ord[i];
			des[cur] = 1;
			long[] ldp = new long[]{1};
			for(int e : g[cur]){
				if(par[cur] != e){
					des[cur] += des[e];
					long[] nldp = new long[ldp.length+dp[e].length-1];
					for(int j = 0;j < ldp.length;j++){
						for(int k = 0;k < dp[e].length;k++){
							nldp[j+k] += ldp[j]*dp[e][k];
							nldp[j+k] %= mod;
						}
					}
					ldp = nldp;
				}
			}
			assert ldp.length == des[cur];
			ldp = Arrays.copyOf(ldp, des[cur]+1);
			ldp[des[cur]] = 1;
			dp[cur] = ldp;
		}
		out.println(dp[0][K]);
	}
	
	public static int[][] parents3(int[][] g, int root) {
		int n = g.length;
		int[] par = new int[n];
		Arrays.fill(par, -1);

		int[] depth = new int[n];
		depth[0] = 0;

		int[] q = new int[n];
		q[0] = root;
		for (int p = 0, r = 1; p < r; p++) {
			int cur = q[p];
			for (int nex : g[cur]) {
				if (par[cur] != nex) {
					q[r++] = nex;
					par[nex] = cur;
					depth[nex] = depth[cur] + 1;
				}
			}
		}
		return new int[][] { par, q, depth };
	}
	
	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
	{
//		int n = 2000, m = 99999;
//		Random gen = new Random();
//		StringBuilder sb = new StringBuilder();
//		sb.append(n + " ");
//		sb.append(gen.nextInt(n) + " ");
//		for (int i = 1; i < n; i++) {
//			sb.append(i/2 + " ");
//			sb.append(i + " ");
//		}
//		INPUT = sb.toString();
		
		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");
	}
	
	public static void main(String[] args) throws Exception { new Q234().run(); }
	
	private byte[] inbuf = new byte[1024];
	private 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 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[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private int ni()
	{
		int num = 0, 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 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)); }
}
0