Question

    there is voice recorder which store student voice as per roll number on which it was heard earlier. When the attendance process is 
    complete, it will provide a list which would consist of the number of distinct voices.
    teacher presents the list to you and asks for the roll numbers of students who were not present in class. 

    i am trying to find out roll number of absent students in increasing order.

我写了这个案例，但是一些测试案例失败了。我不确定老师会在清单中提供什么值。

    there are only two inputs :
    1. no of student
    2. result from voice recorder

任何人都可以告诉我们这里缺少什么

public static void main(String args[]) throws Exception {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(br.readLine());
    List<Integer> ll = new ArrayList<>();
    List<Integer> input = new ArrayList<>();

    for (int i = 1; i <= n; i++) {
        ll.add(i);
    }

    String lines = br.readLine();
    String[] strs = lines.trim().split("\\s+");

    for (int i = 0; i < strs.length; i++) {
        input.add(Integer.parseInt(strs[i]));
    }
    for (int i = 0; i < ll.size(); i++) {
        if (input.contains(ll.get(i))) {
            continue;
        }
        else {
            System.out.print(ll.get(i));
        }
        if (i != ll.size() - 1) {
            System.out.print(" ");
        }
    }
}

Answer 1

这很好用，每个测试用例都通过了。

public static void main(String[] args) throws NumberFormatException, IOException {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int stdCount = Integer.parseInt(br.readLine());
    String rollNumbers = br.readLine();
    
    TreeSet<Integer> presentStudents = new TreeSet<Integer>();
    String[] rollNoArr = rollNumbers.split(" ");
    
    for(String s : rollNoArr) {
        presentStudents.add(Integer.valueOf(s.trim()));
    }
    
    for(int i = 1; i <= stdCount; i++) {
        if(!presentStudents.contains(i)) {
            System.out.print(i);
            if(i < stdCount) System.out.print(" ");
        }
    }
}

Answer 2

假设我正确地阅读了问题，则首先输入班上的学生总数。每个学生都有一个分配的编号，然后您提供一个由空格分隔的编号列表（对应于班级中的学生）。您的代码缺少一些方括号，这使事情搞砸了。

此外，对于这种特定情况，您的逻辑：

if (true) {
    continue;
}
else{
    // Do something
}

可以通过以下操作使之简单得多

if(!true){
    // Do something
}

这是我修改过的最终代码：

public static void main(String args[]) throws Exception {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(br.readLine());
    List<Integer> ll = new ArrayList<>();
    List<Integer> input = new ArrayList<>();
    for (int i = 1; i <= n; i++) {
        ll.add(i);
    }

    String lines = br.readLine();
    String[] strs = lines.trim().split("\\s+");

    for (int i = 0; i < strs.length; i++) {
        input.add(Integer.parseInt(strs[i]));
    }
    for (int i = 0; i < ll.size(); i++) {
        if (!input.contains(ll.get(i))) {
            System.out.print(ll.get(i));

            if (i != ll.size() - 1) {
                System.out.print(" ");
            }
        }
    }
}

输入：

6
1 3 4

结果为：

2 5 6

Answer 3

////使用Java8的工作代码

{

public static void main(String[] args) throws IOException {

    List<Integer> totalRolls;
    String[] inputRollsWithProxyStudentsRoll;

    try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {

        totalRolls = IntStream
                .rangeClosed(1, Integer.parseInt(br.readLine()))
                .boxed()
                .collect(Collectors.toList());

        inputRollsWithProxyStudentsRoll = br.readLine().trim().split("\\s+");
    }

    List<Integer> rollsWithProxyStudentsRoll = Arrays
            .stream(inputRollsWithProxyStudentsRoll).map(Integer::parseInt)
            .collect(Collectors.toList());


    IntStream
            .range(0, totalRolls.size())
            .filter(i -> !rollsWithProxyStudentsRoll.contains(totalRolls.get(i)))
            .forEach(i -> {
                System.out.print(totalRolls.get(i));
                if (i != totalRolls.size() - 1) System.out.print(" ");
            });
}

}

Answer 4

import java.io.*
import java.util.*;
class Test {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] array = new int[n];
        for (int i = 0; i < n; i++) 
          array[i] = sc.nextInt();
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < n; j++) {
                if (i == array[j]) {
                    break;
                }
                if (j == n - 1 && i != array[j]) {
                    System.out.println(i + " ");
                }
            }
        }
    }
}

课堂Java编程中的代理

4 个答案: