結果

問題 No.1254 補強への架け橋
ユーザー tenten
提出日時 2022-08-16 11:25:15
言語 Java
(openjdk 23)
結果
AC  
実行時間 974 ms / 2,000 ms
コード長 3,581 bytes
コンパイル時間 2,396 ms
コンパイル使用メモリ 80,120 KB
実行使用メモリ 108,004 KB
最終ジャッジ日時 2024-10-03 03:29:30
合計ジャッジ時間 41,236 ms
ジャッジサーバーID
(参考情報)
judge1 / judge2
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 123
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 #
プレゼンテーションモードにする

import java.io.*;
import java.util.*;
public class Main {
static ArrayList<HashMap<Integer, Integer>> graph = new ArrayList<>();
static int[] depths;
static int[] parents;
public static void main(String[] args) throws Exception {
Scanner sc = new Scanner();
int n = sc.nextInt();
ArrayList<Integer> ans = new ArrayList<>();
for (int i = 0; i < n; i++) {
graph.add(new HashMap<>());
}
UnionFindTree uft = new UnionFindTree(n);
int orgA = 0;
int orgB = 0;
for (int i = 1; i <= n; i++) {
int left = sc.nextInt() - 1;
int right = sc.nextInt() - 1;
if (uft.same(left, right)) {
ans.add(i);
orgA = left;
orgB = right;
} else {
uft.unite(left, right);
graph.get(left).put(right, i);
graph.get(right).put(left, i);
}
}
depths = new int[n];
parents = new int[n];
setDepth(0, 0, 0);
setAns(orgA, orgB, ans);
StringBuilder sb = new StringBuilder();
sb.append(ans.size()).append("\n");
for (int i = 0; i < ans.size(); i++) {
if (i > 0) {
sb.append(" ");
}
sb.append(ans.get(i));
}
System.out.println(sb);
}
static void setAns(int left, int right, ArrayList<Integer> ans) {
if (depths[left] < depths[right]) {
setAns(right, left, ans);
return;
}
while (depths[left] > depths[right]) {
ans.add(graph.get(left).get(parents[left]));
left = parents[left];
}
while (left != right) {
ans.add(graph.get(left).get(parents[left]));
left = parents[left];
ans.add(graph.get(right).get(parents[right]));
right = parents[right];
}
}
static void setDepth(int idx, int p, int d) {
depths[idx] = d;
parents[idx] = p;
for (int x : graph.get(idx).keySet()) {
if (x == p) {
continue;
}
setDepth(x, idx, d + 1);
}
}
static class UnionFindTree {
int[] parents;
public UnionFindTree(int size) {
parents = new int[size];
for (int i = 0; i < size; i++) {
parents[i] = i;
}
}
public int find(int x) {
if (x == parents[x]) {
return x;
} else {
return parents[x] = find(parents[x]);
}
}
public boolean same(int x, int y) {
return find(x) == find(y);
}
public void unite(int x, int y) {
parents[find(x)] = find(y);
}
}
}
class Scanner {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringTokenizer st = new StringTokenizer("");
public Scanner() throws Exception {
}
public int nextInt() throws Exception {
return Integer.parseInt(next());
}
public long nextLong() throws Exception {
return Long.parseLong(next());
}
public double nextDouble() throws Exception {
return Double.parseDouble(next());
}
public String next() throws Exception {
while (!st.hasMoreTokens()) {
st = new StringTokenizer(br.readLine());
}
return st.nextToken();
}
}
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