結果

問題 No.763 Noelちゃんと木遊び
ユーザー GrenacheGrenache
提出日時 2019-05-06 18:48:04
言語 Java21
(openjdk 21)
結果
AC  
実行時間 645 ms / 2,000 ms
コード長 4,797 bytes
コンパイル時間 4,171 ms
コンパイル使用メモリ 80,596 KB
実行使用メモリ 77,084 KB
最終ジャッジ日時 2024-06-28 02:14:57
合計ジャッジ時間 14,056 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge2
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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 439 ms
77,084 KB
testcase_01 AC 251 ms
51,188 KB
testcase_02 AC 487 ms
69,844 KB
testcase_03 AC 352 ms
57,052 KB
testcase_04 AC 301 ms
54,136 KB
testcase_05 AC 348 ms
56,524 KB
testcase_06 AC 639 ms
76,696 KB
testcase_07 AC 645 ms
75,888 KB
testcase_08 AC 360 ms
58,580 KB
testcase_09 AC 277 ms
51,304 KB
testcase_10 AC 175 ms
47,104 KB
testcase_11 AC 640 ms
76,960 KB
testcase_12 AC 527 ms
70,120 KB
testcase_13 AC 522 ms
69,964 KB
testcase_14 AC 476 ms
69,456 KB
testcase_15 AC 360 ms
55,744 KB
testcase_16 AC 135 ms
42,476 KB
testcase_17 AC 356 ms
57,864 KB
testcase_18 AC 636 ms
76,912 KB
testcase_19 AC 531 ms
70,084 KB
testcase_20 AC 528 ms
69,824 KB
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ソースコード

diff # 

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

public class Main_yukicoder763 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		List<Set<Integer>> edges = new ArrayList<>(n);
		int[] cnt = new int[n];
		for (int i = 0; i < n; i++) {
			edges.add(new HashSet<>());
		}

		for (int i = 0; i < n - 1; i++) {
			int u = sc.nextInt() - 1;
			int v = sc.nextInt() - 1;
			
			edges.get(u).add(v);
			edges.get(v).add(u);
			cnt[u]++;
			cnt[v]++;
		}

		Queue<Integer> q = new ArrayDeque<>();
		for (int i = 0; i < n; i++) {
			if (cnt[i] == 1) {
				q.add(i);
			}
		}

		int ans = 0;
		while (!q.isEmpty()) {
			int e = q.remove();
			
			if (cnt[e] == 0) {
				continue;
			}

			for (int del : edges.get(e)) {
				if (cnt[del] == 0) {
					continue;
				}
				
				cnt[del] = 0;
				
				for (int ee : edges.get(del)) {
					if (cnt[ee] == 0) {
						continue;
					}

//					edges.get(ee).remove(del);
					
					cnt[ee]--;
					if (cnt[ee] == 0) {
						ans++;
					} else if (cnt[ee] == 1) {
						q.add(ee);
					} else {
						
					}
				}
			}
		}

		pr.println(ans);
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);
			
		solve();
			
		pr.close();
		sc.close();
	}

	static class Scanner {
		BufferedReader br;

		Scanner (InputStream in) {
			br = new BufferedReader(new InputStreamReader(in));
		}

		private boolean isPrintable(int ch) {
			return ch >= '!' && ch <= '~';
		}

		private boolean isCRLF(int ch) {
			return ch == '\n' || ch == '\r' || ch == -1;
		}

		private int nextPrintable() {
			try {
				int ch;
				while (!isPrintable(ch = br.read())) {
					if (ch == -1) {
						throw new NoSuchElementException();
					}
				}

				return ch;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		String next() {
			try {
				int ch = nextPrintable();
				StringBuilder sb = new StringBuilder();
				do {
					sb.appendCodePoint(ch);
				} while (isPrintable(ch = br.read()));

				return sb.toString();
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		int nextInt() {
			try {
				// parseInt from Integer.parseInt()
				boolean negative = false;
				int res = 0;
				int limit = -Integer.MAX_VALUE;
				int radix = 10;

				int fc = nextPrintable();
				if (fc < '0') {
					if (fc == '-') {
						negative = true;
						limit = Integer.MIN_VALUE;
					} else if (fc != '+') {
						throw new NumberFormatException();
					}
					fc = br.read();
				}
				int multmin = limit / radix;

				int ch = fc;
				do {
					int digit = ch - '0';
					if (digit < 0 || digit >= radix) {
						throw new NumberFormatException();
					}
					if (res < multmin) {
						throw new NumberFormatException();
					}
					res *= radix;
					if (res < limit + digit) {
						throw new NumberFormatException();
					}
					res -= digit;

				} while (isPrintable(ch = br.read()));

				return negative ? res : -res;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		long nextLong() {
			try {
				// parseLong from Long.parseLong()
				boolean negative = false;
				long res = 0;
				long limit = -Long.MAX_VALUE;
				int radix = 10;

				int fc = nextPrintable();
				if (fc < '0') {
					if (fc == '-') {
						negative = true;
						limit = Long.MIN_VALUE;
					} else if (fc != '+') {
						throw new NumberFormatException();
					}
					fc = br.read();
				}
				long multmin = limit / radix;

				int ch = fc;
				do {
					int digit = ch - '0';
					if (digit < 0 || digit >= radix) {
						throw new NumberFormatException();
					}
					if (res < multmin) {
						throw new NumberFormatException();
					}
					res *= radix;
					if (res < limit + digit) {
						throw new NumberFormatException();
					}
					res -= digit;

				} while (isPrintable(ch = br.read()));

				return negative ? res : -res;
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		float nextFloat() {
			return Float.parseFloat(next());
		}

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

		String nextLine() {
			try {
				int ch;
				while (isCRLF(ch = br.read())) {
					if (ch == -1) {
						throw new NoSuchElementException();
					}
				}
				StringBuilder sb = new StringBuilder();
				do {
					sb.appendCodePoint(ch);
				} while (!isCRLF(ch = br.read()));

				return sb.toString();
			} catch (IOException e) {
				throw new NoSuchElementException();
			}
		}

		void close() {
			try {
				br.close();
			} catch (IOException e) {
//				throw new NoSuchElementException();
			}
		}
	}

	static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
}
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