Insert Interval

Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary).

You may assume that the intervals were initially sorted according to their start times.

Example 1:

Given intervals [1,3],[6,9], insert and merge [2,5] in as [1,5],[6,9].

Example 2:

Given [1,2],[3,5],[6,7],[8,10],[12,16], insert and merge [4,9] in as [1,2],[3,10],[12,16].

This is because the new interval [4,9] overlaps with [3,5],[6,7],[8,10].

Solution:

/**
 * 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> insert(List<Interval> intervals, Interval newInterval) {
        List<Interval> ans = new ArrayList<>();
        int i=0;
        while(i<intervals.size() && intervals.get(i).end < newInterval.start) ans.add(intervals.get(i++));
        int start = i<intervals.size() ? Math.min(intervals.get(i).start, newInterval.start) : newInterval.start;
        while(i<intervals.size() && intervals.get(i).start <= newInterval.end) i++;
        int end = i>0 ? Math.max(intervals.get(i-1).end, newInterval.end) : newInterval.end;
        ans.add(new Interval(start, end));
        while(i<intervals.size()) ans.add(intervals.get(i++));
        return ans;
    }
}
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