結果

問題 No.763 Noelちゃんと木遊び
ユーザー Grenache
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
このコードへのチャレンジ
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ファイルパターン 結果
other AC * 21
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ソースコード

diff #
プレゼンテーションモードにする

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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