結果

問題 No.1553 Lovely City
ユーザー cyclerecycle9
提出日時 2021-07-29 08:02:25
言語 Java
(openjdk 23)
結果
AC  
実行時間 1,169 ms / 2,000 ms
コード長 6,594 bytes
コンパイル時間 2,701 ms
コンパイル使用メモリ 85,240 KB
実行使用メモリ 113,016 KB
最終ジャッジ日時 2024-09-14 05:38:25
合計ジャッジ時間 27,810 ms
ジャッジサーバーID
(参考情報)
judge3 / judge4
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 * 2
other AC * 26
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.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.*;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.io.UncheckedIOException;
import java.lang.reflect.Field;
import java.nio.CharBuffer;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.StandardCharsets;
public class Main {
static final long MOD=1000000007;
static final long MOD1=998244353;
static int ans=0;
public static void main(String[] args){
PrintWriter out = new PrintWriter(System.out);
InputReader sc=new InputReader(System.in);
int N = sc.nextInt();
int M = sc.nextInt();
int ans = 0;
ArrayList<Integer>[] E = new ArrayList[N];
for (int i = 0; i < E.length; i++) {
E[i] = new ArrayList<>();
}
UnionFindTree uTree = new UnionFindTree(N);
int[] deg = new int[N];
for (int i = 0; i < M; i++) {
int a = sc.nextInt()-1;
int b = sc.nextInt()-1;
deg[b]++;
uTree.union(a, b, 1);
E[a].add(b);
}
ArrayList<Integer>[] group = new ArrayList[N];
for (int i = 0; i < group.length; i++) {
group[i] = new ArrayList<>();
}
for (int i = 0; i < N; i++) {
group[uTree.find(i)].add(i);
}
ArrayList<String> anStrings = new ArrayList<>();
for (int i = 0; i < group.length; i++) {
if(group[i].size()<=1)continue;
ArrayDeque<Integer> deq = new ArrayDeque<>();
ArrayList<Integer> topo = new ArrayList<>();
for (int v: group[i]) {
if(deg[v]==0)deq.add(v);
}
int c = 0;
while (!deq.isEmpty()) {
int v = deq.pollFirst();
topo.add(v);
c++;
for (Integer to: E[v]) {
deg[to]--;
if (deg[to]==0) {
deq.add(to);
}
}
}
if (c==group[i].size()) {
for (int j = 0; j < topo.size()-1; j++) {
anStrings.add((topo.get(j)+1)+" "+(topo.get(j+1)+1));
}
ans += group[i].size()-1;
}else {
ans += group[i].size();
int size = group[i].size();
for (int j = 0; j < group[i].size(); j++) {
int from = group[i].get((j-1+size)%size)+1;
int to = group[i].get(j%size)+1;
anStrings.add(from+" "+to);
}
}
}
out.println(ans);
for (String string : anStrings) {
out.println(string);
}
out.flush();
}
static class UnionFindTree{
int[] par;
int[] rank;
int[] size;
int[] diff_weight;
int arraysize;
public UnionFindTree(int n) {
this.par=new int[n];
this.rank=new int[n];
this.size=new int[n];
this.diff_weight=new int[n];
arraysize=n;
for (int i = 0; i < arraysize; i++) {
set(i);
}
}
public void set(int i) {
par[i]=i;
rank[i]=0;
size[i]=1;
diff_weight[i]=0;
}
public void union(int x,int y,int w) {
w += weight(x);
w -= weight(y);
int rootx=find(x);
int rooty=find(y);
if (rootx==rooty) {
return;
}
if (rank[rootx]>rank[rooty]) {
par[rooty]=rootx;
diff_weight[rooty] = w;
size[rootx]+=size[rooty];
}
else if (rank[rootx]<rank[rooty]) {
par[rootx]=rooty;
w=-w;
diff_weight[rootx] = w;
size[rooty]+=size[rootx];
}
else {
par[rooty]=rootx;
diff_weight[rooty] = w;
rank[rootx]++;
size[rootx]+=size[rooty];
}
}
public int find(int x) {
if(par[x] == x) return x;
int r = find(par[x]);
diff_weight[x] += diff_weight[par[x]];
return par[x] = r;
}
public int weight(int x) {
find(x);
return diff_weight[x];
}
public int size(int i) {
return size[find(i)];
}
public int diff(int x, int y) {
return weight(y) - weight(x);
}
public boolean same(int x, int y) {
return find(x) == find(y);
}
}
static class InputReader {
private InputStream in;
private byte[] buffer = new byte[1024];
private int curbuf;
private int lenbuf;
public InputReader(InputStream in) {
this.in = in;
this.curbuf = this.lenbuf = 0;
}
public boolean hasNextByte() {
if (curbuf >= lenbuf) {
curbuf = 0;
try {
lenbuf = in.read(buffer);
} catch (IOException e) {
throw new InputMismatchException();
}
if (lenbuf <= 0)
return false;
}
return true;
}
private int readByte() {
if (hasNextByte())
return buffer[curbuf++];
else
return -1;
}
private boolean isSpaceChar(int c) {
return !(c >= 33 && c <= 126);
}
private void skip() {
while (hasNextByte() && isSpaceChar(buffer[curbuf]))
curbuf++;
}
public boolean hasNext() {
skip();
return hasNextByte();
}
public String next() {
if (!hasNext())
throw new NoSuchElementException();
StringBuilder sb = new StringBuilder();
int b = readByte();
while (!isSpaceChar(b)) {
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}
public int nextInt() {
if (!hasNext())
throw new NoSuchElementException();
int c = readByte();
while (isSpaceChar(c))
c = readByte();
boolean minus = false;
if (c == '-') {
minus = true;
c = readByte();
}
int res = 0;
do {
if (c < '0' || c > '9')
throw new InputMismatchException();
res = res * 10 + c - '0';
c = readByte();
} while (!isSpaceChar(c));
return (minus) ? -res : res;
}
public long nextLong() {
if (!hasNext())
throw new NoSuchElementException();
int c = readByte();
while (isSpaceChar(c))
c = readByte();
boolean minus = false;
if (c == '-') {
minus = true;
c = readByte();
}
long res = 0;
do {
if (c < '0' || c > '9')
throw new InputMismatchException();
res = res * 10 + c - '0';
c = readByte();
} while (!isSpaceChar(c));
return (minus) ? -res : res;
}
public double nextDouble() {
return Double.parseDouble(next());
}
public int[] nextIntArray(int n) {
int[] a = new int[n];
for (int i = 0; i < n; i++)
a[i] = nextInt();
return a;
}
public double[] nextDoubleArray(int n) {
double[] a = new double[n];
for (int i = 0; i < n; i++)
a[i] = nextDouble();
return a;
}
public long[] nextLongArray(int n) {
long[] a = new long[n];
for (int i = 0; i < n; i++)
a[i] = nextLong();
return a;
}
public char[][] nextCharMap(int n, int m) {
char[][] map = new char[n][m];
for (int i = 0; i < n; i++)
map[i] = next().toCharArray();
return map;
}
}
}
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