コード
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.TreeMap;
public class TaskC {
private static class Task {
void solve(FastScanner in, PrintWriter out) {
int N = in.nextInt();
int Q = in.nextInt();
TreeMap<Integer, Integer> notifications = new TreeMap<>();
TreeMap<Integer, Integer> unread = new TreeMap<>();
TreeMap<Integer, ArrayList<Integer>> map = new TreeMap<>();
for (int i = 0; i < Q; i++) {
int type = in.nextInt();
if (type == 1) {
int x = in.nextInt();
int notificationId = notifications.size();
notifications.put(notificationId, x);
unread.put(notificationId, x);
ArrayList<Integer> list = map.get(x);
if (list == null) map.put(x, list = new ArrayList<>());
list.add(notificationId);
}
if (type == 2) {
int x = in.nextInt();
ArrayList<Integer> list = map.get(x);
if (list != null) {
for (int id : list) {
unread.remove(id);
}
list.clear();
}
}
if (type == 3) {
int t = in.nextInt();
Map.Entry<Integer, Integer> first = unread.firstEntry();
while (first != null && first.getKey() < t) {
unread.remove(first.getKey());
first = unread.firstEntry();
}
}
out.println(unread.size());
}
}
}
ここから下はテンプレートです。
public static void main(String[] args) {
OutputStream outputStream = System.out;
FastScanner in = new FastScanner();
PrintWriter out = new PrintWriter(outputStream);
Task solver = new Task();
solver.solve(in, out);
out.close();
}
private static class FastScanner {
private final InputStream in = System.in;
private final byte[] buffer = new byte[1024];
private int ptr = 0;
private int bufferLength = 0;
private boolean hasNextByte() {
if (ptr < bufferLength) {
return true;
} else {
ptr = 0;
try {
bufferLength = in.read(buffer);
} catch (IOException e) {
e.printStackTrace();
}
if (bufferLength <= 0) {
return false;
}
}
return true;
}
private int readByte() {
if (hasNextByte()) return buffer[ptr++];
else return -1;
}
private static boolean isPrintableChar(int c) {
return 33 <= c && c <= 126;
}
private void skipUnprintable() {
while (hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;
}
boolean hasNext() {
skipUnprintable();
return hasNextByte();
}
public String next() {
if (!hasNext()) throw new NoSuchElementException();
StringBuilder sb = new StringBuilder();
int b = readByte();
while (isPrintableChar(b)) {
sb.appendCodePoint(b);
b = readByte();
}
return sb.toString();
}
long nextLong() {
if (!hasNext()) throw new NoSuchElementException();
long n = 0;
boolean minus = false;
int b = readByte();
if (b == '-') {
minus = true;
b = readByte();
}
if (b < '0' || '9' < b) {
throw new NumberFormatException();
}
while (true) {
if ('0' <= b && b <= '9') {
n *= 10;
n += b - '0';
} else if (b == -1 || !isPrintableChar(b)) {
return minus ? -n : n;
} else {
throw new NumberFormatException();
}
b = readByte();
}
}
double nextDouble() {
return Double.parseDouble(next());
}
double[] nextDoubleArray(int n) {
double[] array = new double[n];
for (int i = 0; i < n; i++) {
array[i] = nextDouble();
}
return array;
}
double[][] nextDoubleMap(int n, int m) {
double[][] map = new double[n][];
for (int i = 0; i < n; i++) {
map[i] = nextDoubleArray(m);
}
return map;
}
public int nextInt() {
return (int) nextLong();
}
public int[] nextIntArray(int n) {
int[] array = new int[n];
for (int i = 0; i < n; i++) array[i] = nextInt();
return array;
}
public long[] nextLongArray(int n) {
long[] array = new long[n];
for (int i = 0; i < n; i++) array[i] = nextLong();
return array;
}
public String[] nextStringArray(int n) {
String[] array = new String[n];
for (int i = 0; i < n; i++) array[i] = next();
return array;
}
public char[][] nextCharMap(int n) {
char[][] array = new char[n][];
for (int i = 0; i < n; i++) array[i] = next().toCharArray();
return array;
}
}
}
