查找丢失号码的Java程序

鲍勃还是个小孩子，刚刚学会了数数。他坐在他的房子里，开始玩他的玩具数量。他的左边有n个玩具号码，右手有n个玩具的数量。突然他的母亲叫他，他把所有的数字混合起来就走了。当他回来时，他意识到他忘记了他所拥有的数字的计数。给定所有玩具数字，帮助他找到数组中存在的n值或打印 -1。

例子

Input: 5 7 4 3 2 6

Output: 5

Explanation: There are 6 toy numbers out of which one is the length hence we print 5.

Input: 10 14 11 15

Output: -1

Explanation: There are 4 toy numbers but we do not have 3 as the value in the array hence we print -1.

方法

解决方案非常简单。我们可以只接受字符串中的输入并计算空格的数量，这将是数组的实际长度。

算法

1. Take the input as string.
2. Count the number of spaces present in the string.
3. If the number of spaces present is equal to any of the element present in the array then print that number else print -1.
4. To find the element is present or not, we use string.indexOf() method.

它是如何工作的？

• 当我们将输入作为字符串时，字符串中存在的元素数等于存在的空格数 +1。
• 元素的实际数量等于字符串-1 中存在的元素数量。

Required answer = number of spaces +1 -1 = number of spaces

我执行：

Java

// Java program to find the lost count
  
import java.util.*;
public class GFG {
  
    // find lost count
    public static void findLostCount(String s)
    {
  
        // counting the number of elements using the split
        // function -1
        int count = s.split(" ").length - 1;
  
        // if the value count is present then print count
        // else print -1
        if (s.indexOf(Integer.toString(count)) != -1)
            System.out.println("Number of elements "
                               + count);
        else
            System.out.println(-1);
    }
  
    public static void main(String args[])
    {
        Scanner in = new Scanner(System.in);
  
        // Taking input as string
        String s = "5 7 4 3 2 6";
  
        findLostCount(s);
    }
}

输出

Number of elements 5