连续整数

import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int length = in.nextInt();
        int[] numbers = new int[length];
        for (int i = 0; i<length; i++){
            numbers[i]=in.nextInt();
        }
        if(length==1) {
        	if(numbers[0]==1) {
        		System.out.println(2);
        	}
        	else {
        		System.out.print((numbers[0]-1) +" "+ (numbers[0]+1));
        	}
        }
        else {
        	 Arrays.sort(numbers);
             ArrayList<Integer> index = new ArrayList<Integer>();
                 for(int i = 0; i<length-1; i++){
                     if(numbers[i+1]-numbers[i]==0||numbers[i+1]-numbers[i]>2){
                             System.out.println("mistake");
                             return; 
                     }
                     if(numbers[i+1]-numbers[i]==2) {
                     	index.add(i);
                     }
                 }
                 if(index.size()==0) {
                	 if(numbers[0]==1) {
                		 System.out.print((numbers[length-1]+1));
                	 }
                	 else {
                		 System.out.print((numbers[0]-1) +" "+ (numbers[length-1]+1));
                	 }
                 }
                 else if (index.size()==1) {
                 	System.out.println(numbers[index.get(0)]+1);
                 }
                 else {
                 	System.out.println("mistake");
                 }
                          
         }
        }
       
}

import java.util.Arrays; import java.util.Scanner; public class Main { public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);  int n,k,count=0;  n=sc.nextInt();  int[] a=new int[n];  for(int i=0;i<n ;i++)
            a[i]=sc.nextInt();  Arrays.sort(a);  k=a[0];//把排序后数组的第一个数赋值给一个常量  for(int i=1;i<n;i++)//计算有多少个相邻数字差值大于1的情况存在，并把数量计入count  { if(a[i]==a[i-1]+1) continue;  else count++;  } for(int i=0;i<n;i++,k++){//开始遍历数组，开始k的值和啊a[0]相同，每次k++寻找差值大于1的数  if(a[i]!=k&&a[i]==k+1&&count==1)//如果数组和k的值不相等，且整个数组中只有这一种情况存在(即count==1)，则这个值为所求值  {
                System.out.print(k);  System.exit(0);  } else if(a[i]!=k&&a[i]!=k+1||count>1)//如果数组和k的值不相同，但是k和数组的差值大于1，则这种情况没有可能的数，并且如果count>1，也不存在  {
                System.out.print("mistake");  System.exit(0);  }
        }//整个数组是一个有序数列，如果所有数之间的差值都为1，则进行如下判断  if(a[0]==1) {//如果这个数组第一个数为1，则只可能是末尾丢失，所求数位数组最后一个数+1  System.out.print(a[n-1]+1);  } else System.out.print(a[0]-1+" "+(a[n-1]+1));//如果数组第一个数不是1，根据题意判断有两个值，即头-1尾+1  }
}

public class Main {
    public static void main(String[] args) {
        java.util.Scanner sc = new java.util.Scanner(System.in);
        int n = sc.nextInt();
        int[] numbers = new int[n];
        for (int i = 0; i < n; i++) {
            numbers[i] = sc.nextInt();
        }
        guess(numbers);
    }
    private static void guess(int[] numbers) {
        if (numbers.length == 0) {
            mistake();
        } else if (numbers.length == 1) {
            print(numbers[0] - 1, numbers[0] + 1);
        } else {
            int min = numbers[0], max = numbers[0], sum = numbers[0], first = numbers[0];
            boolean[] bitArr = new boolean[numbers.length * 2 + 1];
            bitArr[numbers.length] = true;
            for (int i = 1; i < numbers.length; i++) {
                sum += numbers[i];
                //以first为参照物，将数字对应位数置为true
                int index = numbers[i] - first;
                if ((index > 0 && index <= numbers.length) || (index < 0 && -index <= numbers.length)) {
                    bitArr[numbers.length - index] = true;
                } else if (index != 0) {//数字间距离过大，无法连续
                    mistake();
                    return;
                }
                if (numbers[i] > max) {
                    max = numbers[i];
                }
                if (numbers[i] < min) {
                    min = numbers[i];
                }
            }
            int actualCount = numbers.length;
            //求不重复数字个数
            int uniqueCount = 0;
            for (int i = 0; i < bitArr.length; i++) {
                if (bitArr[i]) {
                    uniqueCount++;
                }
            }
            if (actualCount != uniqueCount) {
                mistake();
                return;
            }
            //期望的数字个数
            int expectedCount = max - min + 1;
            //缺少的数字个数
            int lackCount = expectedCount - uniqueCount;
            if (lackCount == 0) {//数列连续
                print(min - 1, max + 1);
            } else if (lackCount == 1) {//中间缺少一个
                print(0, (max + min) * (numbers.length + 1) / 2 - sum);
            } else {//缺少多个
                mistake();
            }
        }
    }
    private static void mistake() {
        System.out.println("mistake");
    }
    private static void print(int i, int j) {
        if (i > 0) {
            System.out.println(i + " " + j);
        } else {
            System.out.println(j);
        }
    }
}

}