import org.junit.Test;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

public class CourseTest {

    private static class Course {
        public int start;
        public int end;
        public int size;

        public int getStart() {
            return start;
        }

        public int getEnd() {
            return end;
        }

        public int getSize() {
            return size;
        }

        public Course(int start, int end) {
            this.start = start;
            this.end = end;
            this.size = end - start;
        }

        @Override
        public String toString() {
            return "Course{" +
                    "start=" + start +
                    ", end=" + end +
                    '}';
        }
    }


    private List<Course> getMaxCourse(List<Course> courses) {
        courses.sort(Comparator.comparing(Course::getStart));
        List<List<Course>> coursesVariants = new ArrayList<>();

        for(int i =0; i < courses.size(); i++){
            coursesVariants.add(getVariantStartFrom(i, courses));
        }
        coursesVariants.sort(Comparator.comparing(List::size));
        return coursesVariants.get(coursesVariants.size() - 1);
    }

    private List<Course> getVariantStartFrom(int i, List<Course> sortedCourses) {
        List<Course> variant = new ArrayList<>();
        Course minimumSizeCourseWithThisStartDate = sortedCourses.get(i);
        for(; i < sortedCourses.size(); i++) {
            if(sortedCourses.size() - 1  == i){
                if(minimumSizeCourseWithThisStartDate.start < sortedCourses.get(i).start) {
                    variant.add(minimumSizeCourseWithThisStartDate);
                    minimumSizeCourseWithThisStartDate = sortedCourses.get(i);
                    variant.add(sortedCourses.get(i));
                }else {
                    if(minimumSizeCourseWithThisStartDate.size >  sortedCourses.get(i).size) {
                        variant.add(sortedCourses.get(i));
                    }
                }

                continue;
            }


            if(minimumSizeCourseWithThisStartDate.size >  sortedCourses.get(i).size) {
                minimumSizeCourseWithThisStartDate = sortedCourses.get(i);
            }

            if(minimumSizeCourseWithThisStartDate.start < sortedCourses.get(i).start) {
                variant.add(minimumSizeCourseWithThisStartDate);
                minimumSizeCourseWithThisStartDate = sortedCourses.get(i);
                continue;
            }


//            while(sortedCourses.get(i).start < ){
//            }
        }
        return variant;
    }


    @Test
    public void test() {
        List<Course> course = new ArrayList<>(List.of(new Course(1,2),
                new Course(1,4),
                new Course(2,3),
                new Course(3,4),
                new Course(1,3)));

        List<Course> maxVariant = getMaxCourse(course);
        System.out.println(maxVariant.toString());
    }

    @Test
    public void test2() {
        List<Course> course = new ArrayList<>(List.of(
                new Course(1,4),
                new Course(2,3),
                new Course(3,4)));

        List<Course> maxVariant = getMaxCourse(course);
        System.out.println(maxVariant.toString());
    }
}