第四题，降序或升序最小的取法 import java.util.ArrayList; import java.util.Scanner; public class Main {     private static int min = Integer.MAX_VALUE;     public static void main(String[] args) {         Scanner scan =new Scanner(System.in);         int n =scan.nextInt();         min=n;         int[] list =new int[n];         for(int i =0;i<n;i++) {             list[i]=scan.nextInt();         }         search(list,0);         System.out.println(min);     }     private static void search(int[] integers,int count) {         count++;         if(count>min)             return;         ArrayList<Integer> copy =new ArrayList<Integer>();         for(Integer i :integers) {             copy.add(i);         }         //升序规则          for(int i=integers.length-1;i>=0;i--) {             if(i==0) {                 if(integers[i]>Integer.MIN_VALUE) {                     copy.remove(i);                 }             }else              if(integers[i]>integers[i-1]) {                 copy.remove(i);             }         }         if(copy.size()==0) {             if(count<min) {                 min=count;             }             return;         }         int[] copyArray = new int[copy.size()];         for(int i =0;i<copy.size();i++) {             copyArray[i]=copy.get(i);         }         search(copyArray,count);         copy.clear();         for(Integer i :integers) {             copy.add(i);         }         //降序规则         //升序规则          for(int i=integers.length-1;i>=0;i--) {             if(i==0) {                 if(integers[i]<Integer.MAX_VALUE) {                     copy.remove(i);                 }             }else             if(integers[i]<integers[i-1]) {                 copy.remove(i);             }         }         if(copy.size()==0) {             if(count<min) {                 min=count;             }             return;         }         copyArray = new int[copy.size()];         for(int i =0;i<copy.size();i++) {             copyArray[i]=copy.get(i);         }         search(copyArray,count);         } }