結果
| 問題 |
No.470 Inverse S+T Problem
|
| コンテスト | |
| ユーザー |
 Grenache
|
| 提出日時 | 2018-03-19 21:40:26 |
| 言語 | Java (openjdk 23) |
| 結果 |
AC
|
| 実行時間 | 166 ms / 2,000 ms |
| コード長 | 7,652 bytes |
| コンパイル時間 | 6,148 ms |
| コンパイル使用メモリ | 81,320 KB |
| 実行使用メモリ | 59,560 KB |
| 最終ジャッジ日時 | 2024-12-22 13:49:46 |
| 合計ジャッジ時間 | 8,146 ms |
|
ジャッジサーバーID （参考情報） |
judge2 / judge3 |
（要ログイン）
| ファイルパターン | 結果 |
|---|---|
| sample | AC * 4 |
| other | AC * 27 |
ソースコード
import java.io.*;
import java.util.*;
public class Main_yukicoder470_1 {
private static Scanner sc;
private static Printer pr;
private static void solve() {
int n = sc.nextInt();
char[][] u = new char[n][];
for (int i = 0; i < n; i++) {
u[i] = sc.next().toCharArray();
}
if (n > 52) {
pr.println("Impossible");
return;
}
int V = n * 2;
SCC scc = new SCC(V);
for (int i = 0; i < n; i++) {
for (int j = i + 1; j < n; j++) {
if (u[i][0] == u[j][0]) {
scc.add_edge(i, j + n);
scc.add_edge(j, i + n);
}
if (u[i][1] == u[j][1] && u[i][2] == u[j][2]) {
scc.add_edge(i, j + n);
scc.add_edge(j, i + n);
}
if (u[i][2] == u[j][2]) {
scc.add_edge(i + n, j);
scc.add_edge(j + n, i);
}
if (u[i][0] == u[j][0] && u[i][1] == u[j][1]) {
scc.add_edge(i + n, j);
scc.add_edge(j + n, i);
}
if (u[i][0] == u[j][2]) {
scc.add_edge(i, j);
scc.add_edge(j + n, i + n);
}
if (u[i][1] == u[j][0] && u[i][2] == u[j][1]) {
scc.add_edge(i, j);
scc.add_edge(j + n, i + n);
}
if (u[i][2] == u[j][0]) {
scc.add_edge(i + n, j + n);
scc.add_edge(j, i);
}
if (u[i][0] == u[j][1] && u[i][1] == u[j][2]) {
scc.add_edge(i + n, j + n);
scc.add_edge(j, i);
}
}
}
scc.scc();
for (int i = 0; i < n; i++) {
if (scc.cmp[i] == scc.cmp[i + n]) {
pr.println("Impossible");
return;
}
}
for (int i = 0; i < n; i++) {
if (scc.cmp[i] > scc.cmp[i + n]) {
pr.printf("%c %c%c\n", u[i][0], u[i][1], u[i][2]);
} else {
pr.printf("%c%c %c\n", u[i][0], u[i][1], u[i][2]);
}
}
}
// SCC O(V + E)
private static class SCC {
private int V;
private List<List<Integer>> edges;
private List<List<Integer>> redges; // 逆向きの辺
private List<Integer> vs; // 帰りがけ順の並び
private int[] used; // 0:White, 1:Gray, 2:Black
private int[] cmp; // 属する強連結成分のトポロジカル順序
private SCC(int V) {
this.V = V;
edges = new ArrayList<>(V);
redges = new ArrayList<>(V);
for (int i = 0; i < V; i++) {
edges.add(new ArrayList<>());
redges.add(new ArrayList<>());
}
vs = new ArrayList<>(V);
used = new int[V];
cmp = new int[V];
}
private void add_edge(int from, int to) {
edges.get(from).add(to);
redges.get(to).add(from);
}
private int scc() {
// dfs
for (int v = 0; v < V; v++) {
if (used[v] != 0) {
continue;
}
Deque<Integer> st = new ArrayDeque<>();
st.push(v);
while (!st.isEmpty()) {
int e = st.peek();
if (used[e] == 2) {
st.pop();
} else if (used[e] == 1) {
// postorder
vs.add(e);
used[e] = 2;
st.pop();
} else {
// preorder
used[e] = 1;
for (int next : edges.get(e)) {
if (used[next] == 2) {
// 前進辺または横断辺
continue;
} else if (used[next] == 1) {
// 後退辺
continue;
}
st.push(next);
}
}
}
}
Arrays.fill(used, 0);
// rdfs
int k = 0;
for (int i = vs.size() - 1; i >= 0; i--) {
int v = vs.get(i);
if (used[v] != 0) {
continue;
}
Deque<Integer> st = new ArrayDeque<>();
st.push(v);
while (!st.isEmpty()) {
int e = st.peek();
if (used[e] == 2) {
st.pop();
} else if (used[e] == 1) {
// postorder
used[e] = 2;
st.pop();
} else {
// preorder
cmp[e] = k;
used[e] = 1;
for (int next : redges.get(e)) {
if (used[next] == 2) {
// 前進辺または横断辺
continue;
} else if (used[next] == 1) {
// 後退辺
continue;
}
st.push(next);
}
}
}
k++;
}
return k;
}
// v が属する強連結成分のトポロジカル順序
private int getCmp(int v) {
return cmp[v];
}
}
// ---------------------------------------------------
public static void main(String[] args) {
sc = new Scanner(System.in);
pr = new Printer(System.out);
solve();
pr.close();
sc.close();
}
@SuppressWarnings("unused")
private 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();
}
}
}
private static class Printer extends PrintWriter {
Printer(PrintStream out) {
super(out);
}
}
}