DNA비밀번호

https://www.acmicpc.net/problem/12891

12891번: DNA 비밀번호

package BaekJoon.SlidingWindow;

import java.util.*;
import java.io.*;
public class DNA비밀번호 {

	static int p,s;
	static int answer=0;
	static int a,c,g,t;
	public static boolean check(HashMap<Character,Integer>hm) {
		
			Set<Character> key = hm.keySet();
			for(Iterator it =key.iterator(); it.hasNext();) {
				
				Character keyValue = (Character)it.next();
				if(keyValue=='A' && hm.get(keyValue)<a) {return false;}	
				else if(keyValue=='C' && hm.get(keyValue)<c) {return false;}
				else if(keyValue=='G' && hm.get(keyValue)<g) {return false;}
				else if(keyValue=='T' && hm.get(keyValue)<t) {return false;}
				
			}
		
		return true;
	}
	
	
	public static void main(String[] args) throws IOException {
		
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(br.readLine());
		
		p =Integer.parseInt(st.nextToken());
		s = Integer.parseInt(st.nextToken());
		
		HashMap<Character,Integer>hm = new HashMap<>();
		String str = br.readLine();
		
		st = new StringTokenizer(br.readLine());
		
		int n = Integer.parseInt(st.nextToken());
		a = n;
		hm.put('A', 0);
		n = Integer.parseInt(st.nextToken());
		 c = n;
		hm.put('C', 0);
		n = Integer.parseInt(st.nextToken());
		g = n;
		hm.put('G', 0);
		n = Integer.parseInt(st.nextToken());
		t = n;
		hm.put('T', 0);
		
		for(int i=0; i<s; i++) {
			
			char cc = str.charAt(i);
			hm.put(cc, hm.get(cc)+1);
		}
		
		if(check(hm))answer++;
		
		for(int i=1; i+s-1<p; i++) {
			
			char prevc = str.charAt(i-1);
			char nextc = str.charAt(i+s-1);
			hm.put(prevc, hm.get(prevc)-1);
			hm.put(nextc, hm.get(nextc)+1);
			
			if(check(hm))answer++;
			
		}
		
		
		System.out.println(answer);
		
	}
	
	
}