Merge Intervals

Given a collection of intervals, merge all overlapping intervals.

For example,

Given 

[1,3],[2,6],[8,10],[15,18]

,

return 

[1,6],[8,10],[15,18]

.

/**
* Definition for an interval.
* public class Interval {
* int start;
* int end;
* Interval() { start = 0; end = 0; }
* Interval(int s, int e) { start = s; end = e; }
* }
*/
public class Solution {
public List<Interval> merge(List<Interval> intervals) {

ArrayList<Interval> result = new ArrayList<Interval>();
if (intervals == null || intervals.size() <= 1)
return intervals;

Comparator<Interval> comp = new Comparator<Interval>() {
public int compare(Interval i1, Interval i2) {
return i1.start - i2.start;
}
};
Collections.sort(intervals, comp);

result.add(intervals.get(0));
for (int i = 1; i < intervals.size(); i++) {
if (result.get(result.size() - 1).end >= intervals.get(i).start) {
result.get(result.size() - 1).end = Math.max(intervals.get(i).end, result.get(result.size() - 1).end);
} else {
result.add(intervals.get(i));
}
}

return result;
}

}