Leetcode 57. 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) {

size_t n = intervals.size();

size_t i = 0;
for (; i != n && intervals[i].end < newInterval.start; ++i)
;
if (i == n) {
intervals.push_back(newInterval);
return intervals;
}

size_t j = i;
for (; j != n && intervals[j].start <= newInterval.end; ++j)
;

newInterval.start = min(newInterval.start, intervals[i].start);
newInterval.end = max(newInterval.end, intervals[j - 1].end);

vector<Interval>::iterator it = intervals.erase(intervals.begin() + i, intervals.begin() + j);
intervals.insert(it, newInterval);

return intervals;
}

};