Student number 0-999 randomly generates test scores for each student (0-100 points), finds 10 best scores, and the student obtains the highest number of 5 points for the same score, and lists the student numbers for which the scores are obtained.

Package com.cn;

Import java.util.ArrayList;
Import java.util.Collections;
Import Java.util.Comparator;
Import Java.util.HashMap;
Import java.util.List;
Import Java.util.Map;
Import Java.util.Map.Entry;
Import Java.util.Random;

/**
* Created by Sam on 2017/1/9.
*/
public class Toolclasspractice {
public static void Main (string[] args) {
Int[] score = new INT[101];
The number of occurrences of the collection---key appears, value is the number of occurrences
Map<integer, integer> map_times = new Hashmap<integer, integer> ();
The collection---Key for the Student object is the number, and the value is the fraction
Map<integer, integer> map_stu = new Hashmap<integer, integer> ();
Generate 1000 students
for (int i = 0; i <; i++) {
Random random = new random ();
Randomly generate fractions between 0-100 points
Int J = Random.nextint (101);
Count the number of occurrences of each score
score[j]++;
Map_stu.put (i, j);
}

for (int q = 0; q <=; q++) {
Map_times.put (q, Score[q]);
}

Toolclasspractice t = new Toolclasspractice ();
Student's map collection into the list collection
List<map.entry<integer, integer>> list_stu = new Arraylist<map.entry<integer, Integer>> ();
Number of occurrences Map collection converted to list collection
List<map.entry<integer, integer>> list_times = new Arraylist<map.entry<integer, Integer>> ();

To sort fractions
List_stu = T.sortmapbyvalue (Map_stu);
System.out.println ("10 Highest score:");
for (int a = 0; a <; a++) {
System.out.println (List_stu.get (a). GetValue ());
}

Sort the collection of times
List_times = T.sortmapbyvalue (map_times);

Get the top 5 number of times set
List<map.entry<integer, integer>> list_timestop5 = new Arraylist<map.entry<integer, Integer> > ();
for (int p = 0; p < 5; p++) {
List_timestop5.add (List_times.get (p));
}
Get the top five scores of students with the highest number of points in a collection
System.out.println ("The top five students with the highest scores:");
For (Map.entry<integer, integer> entrytimes:list_timestop5) {
int count = 0;
For (Map.entry<integer, integer> entry:list_stu) {
count++;
if (count = = 1) {
SYSTEM.OUT.PRINTLN ("---" + entrytimes.getkey () + "score has" + entrytimes.getvalue () + "person" + "---");
}

The scores of the Times set are equal to the scores of the students ' collections
if (entrytimes.getkey () = = Entry.getvalue ()) {
System.out.println ("School Number:" + entry.getkey () + "score:" + entry.getvalue ());
}
}
}
}

Sort by value for the map collection
Public List<map.entry<integer, Integer>> sortmapbyvalue (Map<integer, integer> Map) {
Convert map to list collection, list using ArrayList
List<map.entry<integer, integer>> list_data = new ArrayList <map.entry<integer, Integer>> ( Map.entryset ());
Sort by Collections.sort (List i,comparator C) method
Collections.sort (List_data, New Comparator<map.entry<integer, integer>> () {

@Override
public int Compare (Entry<integer, integer> O1, Entry<integer, integer> O2) {
Return (O2.getvalue ()-o1.getvalue ());
}
});
return list_data;
}
}

Student number 0-999 randomly generates test scores for each student (0-100 points), finds 10 best scores, and the student obtains the highest number of 5 points for the same score, and lists the student numbers for which the scores are obtained.