Merge Intervals
At first we sort the intervals by their start property with Collections.sort
,
then we merge next interval to last one by one.
/**
* 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 MergeIntervals {
public List<Interval> merge(List<Interval> intervals) {
Collections.sort(intervals, new Comparator<Interval> () {
public int compare(Interval a, Interval b) {
return a.start - b.start;
}
});
ArrayList<Interval> result = new ArrayList<Interval>();
for (Interval interval : intervals) {
if (result.isEmpty()) {
result.add(interval);
continue;
}
Interval last = result.get(result.size() - 1);
if (last.end < interval.start) {
result.add(interval);
} else {
last.end = Math.max(last.end, interval.end);
}
}
return result;
}
}