Data Stream as Disjoint Intervals

Given a data stream input of non-negative integers a1, a2, ..., an, ..., summarize the numbers seen so far as a list of disjoint intervals.

For example, suppose the integers from the data stream are 1, 3, 7, 2, 6, ..., then the summary will be:

[1, 1]
[1, 1], [3, 3]
[1, 1], [3, 3], [7, 7]
[1, 3], [7, 7]
[1, 3], [6, 7]

Follow up:
What if there are lots of merges and the number of disjoint intervals are small compared to the data stream's size?

Use the same approach as insert interval: use a new list and add intervals to that. It's easier than modify the original interval.

public class SummaryRanges {
    private List intervals;
    /** Initialize your data structure here. */
    public SummaryRanges() {
        intervals = new ArrayList<>();
    }
    
    public void addNum(int val) {
        Interval newInterval = new Interval(val, val);
        List newIntervals = new ArrayList<>();
        int pos = 0;
        for (Interval curr : intervals) {
            if (curr.end + 1 < val) {
                newIntervals.add(curr);
                pos++;
            } else if (curr.start - 1 > val) {
                newIntervals.add(curr);
            } else {
                newInterval.start = Math.min(curr.start, newInterval.start);
                newInterval.end = Math.max(curr.end, newInterval.end);
            }
        }
        newIntervals.add(pos, newInterval);
        intervals = newIntervals;
    }
    
    public List getIntervals() {
        return intervals;
    }
}