[Java] Sorting A Three-Valued Sequence

/* Use the slash-star style comments or the system won't see your
   identification information */
/*
ID: lincans1
LANG: JAVA
TASK: sort3
*/
import java.io.*;
import java.util.*;

public class sort3 {
    
    

	private void swap (int[] array, int a, int b) {
    
    
		int temp = array[a];
		array[a] = array[b];
		array[b] = temp;
	}

	private int count (int[] array) {
    
    
		int[] count = new int[4];
		for (int i : array) {
    
    
			count[i]++;
		}
		count[2] += count[1];
		count[3] += count[2];
		int one_three = 0, three_one = 0, sum = 0;
		for (int i = 0, n = count[1]; i < n; i++) {
    
    
			if (array[i] == 3) {
    
    
				one_three++;
			}
		}
		for (int i = count[1], n = count[2]; i < n; i++) {
    
    
			if (array[i] != 2) {
    
    
				sum++;
			}
		}
		for (int i = count[2], n = count[3]; i < n; i++) {
    
    
			if (array[i] == 1) {
    
    
				three_one++;
			}
		}
		return Math.max(one_three, three_one) + sum;
	}

	public sort3() throws IOException {
    
    
		// Use BufferedReader rather than RandomAccessFile; it's much faster
		BufferedReader f = new BufferedReader(new FileReader("sort3.in"));
		PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("sort3.out")));

		int N = Integer.parseInt(f.readLine());
		int[] array = new int[N];
		for (int i = 0; i < N; i++) {
    
    
			array[i] = Integer.parseInt(f.readLine());
		}
		int ans = count(array);
		out.println(ans);
	    out.close();
	    f.close();
	}
	
	public static void main (String [] args) throws IOException {
    
    
		new sort3();
	}
}