Problem:
血液型

ある学級の生徒の出席番号と ABO 血液型を保存したデータを読み込んで、おのおのの血液型の人数を出力するプログラムを作成してください。なお、ABO 血液型には、A 型、B 型、AB 型、O 型の４種類の血液型があります。

Input

カンマで区切られた出席番号と血液型の組が、複数行に渡って与えられます。出席番号は 1 以上 50 以下の整数、血液型は文字列 "A", "B", "AB" または "O" のいずれかです。生徒の人数は 50 を超えません。

Output

１行目に A 型の人数

２行目に B 型の人数

３行目に AB 型の人数

４行目に O 型の人数

を出力します。

Sample Input

1,B
2,A
3,B
4,AB
5,B
6,O
7,A
8,O
9,AB
10,A
11,A
12,B
13,AB
14,A

Output for the Sample Input

5
4
3
2

Solution in JAVA (judge verdict: Accepted)

import java.util.*;
import java.io.*;
import java.math.*;

public class Main {

	void solve (FastScanner in, PrintWriter out, Methods ms) {

		int[] a = new int[4];
		
		while (in.hasNext() == true) {
			
			String[] temp = in.next().split(",");
			
			if (temp[1].equals("A")) a[0]++;
			else if (temp[1].equals("B")) a[1]++;
			else if (temp[1].equals("AB")) a[2]++;
			else if (temp[1].equals("O")) a[3]++;
			
		}
		
		for (int i=0; i<4; i++) {
			out.println(a[i]);
		}

	}



	public static void main(String[] args) {
		Main main = new Main();
		FastScanner in = new FastScanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		Methods ms = new Methods();
		main.solve(in, out, ms);
		in.close();
		out.close();
	}

	static class Methods {

		public void print (Object... ar) {System.out.println(Arrays.deepToString(ar));}

		public void yesno (PrintWriter out, boolean b) {out.println(b?"Yes":"No");}

		public void YESNO (PrintWriter out, boolean b) {out.println(b?"YES":"NO");}

		public int max (int... ar) {Arrays.sort(ar); return ar[ar.length-1];}

		public int min (int... ar) {Arrays.sort(ar); return ar[0];}

		public long gcd (long a, long b) {return b>0?gcd(b,a%b):a;}

		public long lcm (long a, long b) {return a/gcd(a,b)*b;}

		public long factorial (int i) {
			if (i==1) return 1;
			else return i*factorial(i-1);
		}

		public int manhat (int x1, int y1, int x2, int y2) {
			return Math.abs(x1-x2)+Math.abs(y1-y2);
		}
		public double euclid (double x1, double y1, double x2, double y2) {
			return Math.sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
		}

		public boolean isPrime (int n) {
			if (n==2) return true;
			if (n<2 || n%2==0) return false;
			for (int i=3; i<=Math.sqrt(n); i+=2) if(n%i==0) return false;
			return true;
		}

	}

	static class FastScanner {

		private InputStream in;
		private byte[] buffer = new byte[1024];
		private  int length = 0, p = 0;

		public FastScanner (InputStream stream) {
			in = stream;
		}

		public boolean hasNextByte () {
			if (p < length) return true;
			else {
				p = 0;
				try {length = in.read(buffer);}
				catch (Exception e) {e.printStackTrace();}
				if (length <= 0) return false;
			}
			return true;
		}

		public int readByte () {
			if (hasNextByte() == true) return buffer[p++];
			return -1;
		}

		public boolean isPrintable (int n) {return 33<=n&&n<=126;}

		public void skip () {
			while (hasNextByte() && !isPrintable(buffer[p])) p++;
		}

		public boolean hasNext () {skip(); return hasNextByte();}

		public String next () {
			if (!hasNext()) throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int t = readByte();
			while (isPrintable(t)) {
				sb.appendCodePoint(t);
				t = readByte();
			}
			return sb.toString();
		}

		public String[] nextArray (int n) {
			String[] ar = new String[n];
			for (int i=0; i<n; i++) ar[i] = next();
			return ar;
		}

		public int nextInt () {return Math.toIntExact(nextLong());}

		public int[] nextIntArray (int n) {
			int[] ar = new int[n];
			for (int i=0; i<n; i++) ar[i] = nextInt();
			return ar;
		}

		public long nextLong () {
			if (!hasNext()) throw new NoSuchElementException();
			boolean minus = false;
			int temp = readByte();
			if (temp == '-') {
				minus = true;
				temp = readByte();
			}
			if (temp<'0' || '9'<temp) throw new NumberFormatException();
			long n = 0;
			while (isPrintable(temp)) {
				if ('0'<=temp && temp<='9') {
					n *= 10;
					n += temp - '0';
				}
				else throw new NumberFormatException();
				temp = readByte();
			}
			return minus? -n : n;
		}

		public long[] nextLongArray (int n) {
			long[] ar = new long[n];
			for (int i=0; i<n; i++) ar[i] = nextLong();
			return ar;
		}

		public double nextDouble () {
			return Double.parseDouble(next());
		}

		public double[] nextDoubleArray (int n) {
			double[] ar = new double[n];
			for (int i=0; i<n; i++) ar[i] = nextDouble();
			return ar;
		}

		public void close () {
			try {in.close();}
			catch(Exception e){}
		}

	}

}