[网易编程题] [java] 小易的英语软件

来源牛客网 https://www.nowcoder.com/questionTerminal/f51e08c7642345fb96dd7b29792b0790

题目

小易是班级的英语课代表, 他开发了一款软件开处理他的工作。 小易的软件有一个神奇的功能，能够通过一个百分数来反应你的成绩在班上的位置。“成绩超过班级 ...% 的同学”。 设这个百分数为 p，考了 s 分，则可以通过以下式子计算得出 p： p = ( 分数不超过 s 的人数 - 1) \div÷ 班级总人数 \times 100%×100% 突然一天的英语考试之后，软件突然罢工了，这可忙坏了小易。成绩输入这些对于字写得又快又好的小易当然没有问题，但是计算这些百分数……这庞大的数据量吓坏了他。 于是他来找到你，希望他编一个程序模拟这个软件：给出班级人数 n，以及每个人的成绩，请求出某几位同学的百分数

参考的网上的二分搜索

long[] sortedArr = ... int index = Arrays.binarySearch (sortedArr, value); int first = index; int last = index; if (index >= 0) { while (first > 0 && sortedArr[first-1] == value) first--; while (last < sortedArr.length - 1 && sortedArr[last+1] == value) last++; }

以及java中的格式控制

String resStr = String.format("%.6f ",1.123456789); System.out.println(Double.parseDouble(resStr));

import java.text.DecimalFormat; double a = 1.34566777; DecimalFormat df1 = new DecimalFormat("0.000000");//不够6位补零输出 DecimalFormat df2 = new DecimalFormat("0.######");//不够6位以实际位数输出 你要哪个？ System.out.println(df2.format(a)); //输出 1.345668

这个是通过了测试用例的

import java.util.Arrays;
import java.util.Scanner;
import java.text.DecimalFormat;

public class Main {
    public static void main(String[] args) {
        Scanner Scan = new Scanner(System.in);
        String studentNumStr = Scan.nextLine();
        int studentNumInt = Integer.parseInt(studentNumStr);
        String studentString = Scan.nextLine();
        String[] studentScoresStr = studentString.split(" ");
        int[] studentScoresInt = new int[studentScoresStr.length];
        for(int i = 0;i<studentScoresStr.length;i++){
            studentScoresInt[i] = Integer.parseInt(studentScoresStr[i]);
        }
        int[] studentScoresIntClone = studentScoresInt.clone();
        Arrays.sort(studentScoresIntClone);
        int queryNum =Integer.parseInt(Scan.nextLine());
        int[] queryContent = new int[queryNum];
        for (int i = 0; i < queryNum; i++){
            int studentSequence = Scan.nextInt();
            queryContent[i] = studentSequence;
        }
        for (int element:queryContent){
            double res = ansQuery(element,studentScoresInt,studentScoresIntClone);
            DecimalFormat format = new DecimalFormat("0.000000");
            System.out.println(format.format(res));
        }
    }
    public static double ansQuery(int studentSequence, int[] studentScoresInt, int[] sortedStudentScoresIntClone){
        int target = studentScoresInt[studentSequence-1];
        int index = Arrays.binarySearch(sortedStudentScoresIntClone,target);
        int firstAns = index;
        int lastAns = index;
        if (index >= 0) {
            while (firstAns > 0 && sortedStudentScoresIntClone[firstAns-1] == target)
                firstAns--;
            while (lastAns < sortedStudentScoresIntClone.length - 1 && sortedStudentScoresIntClone[lastAns+1] == target)
                lastAns++;
        }
        double res = (double)lastAns/studentScoresInt.length*100;
        return res;
    }

}

这个是没有注意输入输出的要求：

import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner Scan = new Scanner(System.in);
        System.out.println("请输入学生人数：");
        String studentNumStr = Scan.nextLine();
        int studentNumInt = Integer.parseInt(studentNumStr);
        System.out.println("请输入成绩，以空格分隔：");
        String studentString = Scan.nextLine();
        String[] studentScoresStr = studentString.split(" ");
        int[] studentScoresInt = new int[studentScoresStr.length];
        for(int i = 0;i<studentScoresStr.length;i++){
            studentScoresInt[i] = Integer.parseInt(studentScoresStr[i]);
        }
        int[] studentScoresIntClone = studentScoresInt.clone();
        Arrays.sort(studentScoresIntClone);
        System.out.println("这是输入的成绩："+ Arrays.toString(studentScoresInt));
        int queryNum =Integer.parseInt(Scan.nextLine());
        for (int i = 0; i < queryNum; i++){
            int studentSequence = Scan.nextInt();
            double res = ansQuery(studentSequence,studentScoresInt,studentScoresIntClone);
            System.out.printf("成绩超过班级 %.6f %%的同学\n",res);
        }
    }
    public static double ansQuery(int studentSequence, int[] studentScoresInt, int[] studentScoresIntClone){
        int target = studentScoresInt[studentSequence-1];
        int index = Arrays.binarySearch(sortedStudentScoresIntClone,target);
        int firstAns = index;
        int lastAns = index;
        if (index >= 0) {
            while (firstAns > 0 && sortedStudentScoresIntClone[firstAns-1] == target)
                firstAns--;
            while (lastAns < sortedStudentScoresIntClone.length - 1 && sortedStudentScoresIntClone[lastAns+1] == target)
                lastAns++;
        }
        double res = (double)lastAns/studentScoresInt.length*100;
        return res;
    }

}