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].
Given [1,2],[3,5],[6,7],[8,10],[12,16], insert and merge [4,9] in as [1,2],[3,10],[12,16].
Example 2:
This is because the new interval [4,9] overlaps with [3,5],[6,7],[8,10].
Solution:
first check the intervals, if not intersected with the new interval, push it to the result; otherwise update the new interval (merge them). Finally, find the correct insert position and insert the new interval. Linear complexity. 

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