[백준] 11053 가장 긴 증가하는 부분 수열 (실버2)

https://www.acmicpc.net/problem/11053
LIS 이용

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int N = Integer.parseInt(br.readLine());
        int[] num = new int[N];
        StringTokenizer st = new StringTokenizer(br.readLine());
        for(int i=0;i<N;i++){
            num[i] = Integer.parseInt(st.nextToken());
        }

        ArrayList<Integer> lis = new ArrayList<>();
        for(int n:num){
            int i = Collections.binarySearch(lis,n);
            if(i<0) i = -i-1;

            if(i==lis.size()){
                lis.add(n);
            }
            else{
                lis.set(i,n);
            }
        }
        System.out.println(lis.size());
    }
}