题解 | #最长上升子序列(一)#

import java.util.Arrays;
import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();

        int[] arr = new int[n];

        for (int i = 0; i != n; ++i) {
            arr[i] = in.nextInt();
        }

        int[] len = new int[n];
        // len[i]是以arr[i]结尾的子序列的最大长度
        Arrays.fill(len, 1);

        int result = 1;
        for (int i = 0; i != n; ++i) {
            for (int j = 0; j != i; ++j) {
                // j 一定小于i
                if (arr[i] > arr[j]) {
                    len[i] = Math.max(len[i], len[j] + 1);
                }
            }

            result = Math.max(len[i], result);
        }

        System.out.println(result);
    }
}