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].

/**
 * Definition for an interval.
 * struct Interval {
 *     int start;
 *     int end;
 *     Interval() : start(0), end(0) {}
 *     Interval(int s, int e) : start(s), end(e) {}
 * };
 */
class Solution {
public:
    vector<Interval> insert(vector<Interval> &intervals, Interval newInterval) 
    {
        vector<Interval> v;
        
        int l=-1;
        while(l+1<intervals.size() && intervals[l+1].end<newInterval.start) l=l+1;
        int r=intervals.size();
        while(r-1>=0 && intervals[r-1].start>newInterval.end) r=r-1;
        
        for(int i=0;i<=l;i++)
            v.push_back(intervals[i]);
        //
        l++;r--;
        if(l<intervals.size() && intervals[l].start<newInterval.start) newInterval.start=intervals[l].start;
        if(r>=0 && intervals[r].end>newInterval.end) newInterval.end=intervals[r].end;
        v.push_back(newInterval);
        //
        r++;
        for(int i=r;i<intervals.size();i++)
            v.push_back(intervals[i]);
        return v;
    }
};