Merge Overlapping Intervals

Question

Question : Given a set of time intervals in any order, merge all overlapping intervals into one and output the result which should have only mutually exclusive intervals. Let th

Answer 1

Here is your refined code:

import java.util.*;
import java.lang.*;
import java.io.*;

class Interval {
    int start;
    int end;

    Interval() {
        start = 0;
        end = 0;
    }

    Interval(int s, int e) {
        start = s;
        end = e;
    }
}

public class Ideone {
    public static void main(String[] args) throws java.lang.Exception {
        ArrayList x = new ArrayList();
        Interval i1 = new Interval(1, 3);
        Interval i2 = new Interval(2, 6);
        Interval i3 = new Interval(8, 10);
        Interval i4 = new Interval(15, 18);

        x.add(i1);
        x.add(i2);
        x.add(i3);
        x.add(i4);

        ArrayList r = merge(x);

        for (Interval i : r) {
            System.out.println(i.start + " " + i.end);
        }

    }

    public static ArrayList merge(ArrayList intervals) {

        if (intervals.size() == 0)
            return intervals;
        if (intervals.size() == 1)
            return intervals;

        Collections.sort(intervals, new IntervalComparator());

        Interval first = intervals.get(0);
        int start = first.start;
        int end = first.end;

        ArrayList result = new ArrayList();

        for (int i = 1; i < intervals.size(); i++) {
            Interval current = intervals.get(i);
            if (current.start <= end) {
                end = Math.max(current.end, end);
            } else {
                result.add(new Interval(start, end));
                start = current.start;
                end = current.end;
            }

        }

        result.add(new Interval(start, end));

        return result;

    }
}

class IntervalComparator implements Comparator {
    public int compare(Object o1, Object o2) {
        Interval i1 = (Interval) o1;
        Interval i2 = (Interval) o2;
        return i1.start - i2.start;
    }
}

And name this java file "Ideone.java"