题解 | #合唱队形#正反两次最长递增字序列

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] nums1 = new int[n];
        int[] nums2 = new int[n];
        for (int i = 0; i < n; i++) {
            nums1[i] = sc.nextInt();
            nums2[n - 1 - i] = nums1[i];
        }
        int[] dp1 = new int[n];
        int[] dp2 = new int[n];
        for (int i = 0; i < n; i++) {
            dp1[i] = 1;
            dp2[i] = 1;
            for (int j = 0; j < i; j++) {
                if (nums1[j] < nums1[i] && dp1[j] + 1 > dp1[i]) {
                    dp1[i] = dp1[j] + 1;
                }
                if (nums2[j] < nums2[i] && dp2[j] + 1 > dp2[i]) {
                    dp2[i] = dp2[j] + 1;
                }
            }
        }
        int result = 0;
        for (int i = 0; i < n; i++) {
            if (dp1[i] + dp2[n - 1 - i] > result) {
                result = dp1[i] + dp2[n - 1 - i];
            }
        }
        System.out.println(n - result + 1);
    }
}