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ShowComparator2.java
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78 lines (67 loc) · 1.73 KB
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package class06;
import java.util.Comparator;
import java.util.PriorityQueue;
public class ShowComparator2 {
public static class MyComparator implements Comparator<Integer> {
// 负，第一个参数在前
// 正，第二个参数在前
// 0, 谁放前都行
@Override
public int compare(Integer o1, Integer o2) {
if (o1 < o2) {
return 1;
} else if (o1 > o2) {
return -1;
} else {
return 0;
}
}
}
public static class Student {
public String name;
public int id;
public int age;
public Student(String name, int id, int age) {
this.name = name;
this.id = id;
this.age = age;
}
}
// 谁id大，谁放前！
public static class IdComparator implements Comparator<Student> {
// 如果返回负数，认为第一个参数应该排在前面
// 如果返回正数，认为第二个参数应该排在前面
// 如果返回0，认为谁放前面无所谓
@Override
public int compare(Student o1, Student o2) {
if (o1.id < o2.id) {
return 1;
} else if (o2.id < o1.id) {
return -1;
} else {
return 0;
}
}
}
public static void main(String[] args) {
String str1 = "abc";
String str2 = "b";
System.out.println(str1.compareTo(str2));
PriorityQueue<Student> heap = new PriorityQueue<>(new IdComparator());
Student s1 = new Student("张三", 5, 27);
Student s2 = new Student("李四", 1, 17);
Student s3 = new Student("王五", 4, 29);
Student s4 = new Student("赵六", 3, 9);
Student s5 = new Student("左七", 2, 34);
heap.add(s1);
heap.add(s2);
heap.add(s3);
heap.add(s4);
heap.add(s5);
System.out.println("=========");
while (!heap.isEmpty()) {
Student s = heap.poll();
System.out.println(s.name + ", " + s.id + ", " + s.age);
}
}
}