每天一题(3)-翻转数组

题目

在这里插入图片描述

代码示例

import java.util.Scanner;
public class Main {
    private static void calc(Integer[] nums){
        int start = nums.length - 1;
        int end = nums.length - 1;
        for(int i = 0; i < nums.length - 1; i++){
            if(nums[i] > nums[i + 1]){
                start = i;
                break;
            }
        }
        for(int i = start + 1; i < nums.length - 1; i++){
            if (nums[i] < nums[i + 1]){
                end = i;
                break;
            }
        }
        if(start < end){
            // 判断调换后，能否在连接点递增
            if(start > 0 && nums[start - 1] > nums[end]){
                System.out.println("no");
                return;
            }
            if(end < (nums.length - 1) && nums[start] > nums[end + 1]){
                System.out.println("no");
                return;
            }
            // 判断后面是否是递增
            for(int i = end + 1; i < nums.length - 1; i++){
                if(nums[i] > nums[i + 1]){
                    System.out.println("no");
                    return;
                }
            }
        }
        System.out.println("yes");
    }
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        while(cin.hasNextInt()){
            int n = cin.nextInt();
            Integer[] nums = new Integer[n];
            for(int i = 0; i < n; i++){
                nums[i] = cin.nextInt();
            }
            calc(nums);
        }
    }
}