백준 2798번(Java)

import java.io.*;
import java.util.StringTokenizer;

public class Main {
	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
		StringTokenizer st = new StringTokenizer(br.readLine()," ");
		
		int N = Integer.parseInt(st.nextToken());
		int M = Integer.parseInt(st.nextToken());
		
		int[] cards = new int[N];
		
		st = new StringTokenizer(br.readLine()," ");
		for(int i=0; i<N; i++) {
			cards[i] = Integer.parseInt(st.nextToken());
		}

		int result = search(cards, N, M);
		
		bw.write(String.valueOf(result));

		br.close();
		bw.flush();
		bw.close();
	}

	private static int search(int[] cards, int n, int m) {
		int result = 0;
		
		for(int i=0; i<n-2; i++) {
			for(int j=i+1; j<n-1; j++) {
				for(int k=j+1; k<n; k++) {
					int temp = cards[i]+cards[j]+cards[k];
					
					if(m == temp) { // 세개 합한 값
						return temp;
					}
					
					if(result < temp && temp < m) { // m보다 작은 최대
						result = temp;
					}
				}
			}
		}
		return result;
	}
}