[BOJ] 백준 2295 세 수의 합

Collections함수 binarySearch 사용: 시간 단축 용도

 

[문제]

https://www.acmicpc.net/problem/2295

 

 

[소스 코드]

import java.io.*;
import java.util.*;
public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		int[] arr = new int[n];
		for(int i=0;i<n;i++) {
			arr[i] = Integer.parseInt(br.readLine());
		}
		List<Integer> list = new ArrayList<>();
		for(int i=0;i<n;i++) {
			for(int j=0;j<n;j++) {
				list.add(arr[i] + arr[j]);
			}
		}
		Arrays.sort(arr);
		Collections.sort(list);
		for(int i=n-1;i>=0;i--) {
			for(int j=n-1;j>=0;j--) {
				int diff = arr[i] - arr[j];
				if(Collections.binarySearch(list,diff)>=0) {
					System.out.println(arr[i]);
					return;
				}
			}
		}
	}
}