結果
問題 | No.763 Noelちゃんと木遊び |
ユーザー |
|
提出日時 | 2019-05-06 18:47:33 |
言語 | Java (openjdk 23) |
結果 |
AC
|
実行時間 | 691 ms / 2,000 ms |
コード長 | 4,795 bytes |
コンパイル時間 | 3,865 ms |
コンパイル使用メモリ | 80,672 KB |
実行使用メモリ | 76,860 KB |
最終ジャッジ日時 | 2024-06-28 02:14:18 |
合計ジャッジ時間 | 16,065 ms |
ジャッジサーバーID (参考情報) |
judge2 / judge5 |
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ファイルパターン | 結果 |
---|---|
other | AC * 21 |
ソースコード
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);}}}