题解 | #合唱队#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        //1.录入数据
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] heights = new int[n];
        for (int i = 0; i < n; i++) {
            heights[i] = in.nextInt();
        }
        //2.计算最长递增递减子序列-动态规划
        int[] dp1 = new int[n]; //从左往右，存储最长递增子序列 dp[i]=Map(dp[i],dp[j]+1)
        int[] dp2 = new int[n]; //从右往左，存储最长递减子序列
        Arrays.fill(dp1, 1);
        Arrays.fill(dp2, 1);
        for (int i = 1; i < n; i++) {
            for (int j = 0; j < i; j++) {
                if (heights[i] > heights[j]) {
                    dp1[i] = Math.max(dp1[i], dp1[j] + 1);
                }
            }
        }
        for (int i = n - 2; i >= 0; i--) {
            for (int j = n - 1; j > i; j--) {
                if (heights[i] > heights[j]) {
                    dp2[i] = Math.max(dp2[i], dp2[j] + 1);
                }

            }
        }
        //3.计算最长合唱队
        int max = 1;
        for (int i = 0; i < n; i++) {
            max = Math.max(max, dp1[i] + dp2[i] - 1);
        }
        //4.输出结果
        System.out.print(n - max);

    }
}