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].
思路：和上一题差不多，但要考虑更多问题，注意不要漏掉newInterval可能整体插入（不做merge）的情况
/**
* 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) {
if(intervals.empty()){
intervals.push_back(newInterval);
return intervals;
} //first find the fist end >= newInterval.start
vector<Interval>::iterator startInsertPos = intervals.begin();
for(; startInsertPos < intervals.end(); startInsertPos++){
if(startInsertPos->end >= newInterval.start) break;
}
if(startInsertPos == intervals.end()){ //insert in the final
intervals.push_back(newInterval);
return intervals;
} //find the last start <= newInterval.end
vector<Interval>::iterator endInsertPos = startInsertPos;
for(; endInsertPos < intervals.end(); endInsertPos++){
if(endInsertPos->start > newInterval.end){
break;
}
}
endInsertPos--; //intervals between [startInsertPos, endInsertPos] may need to be merged
//case 1: insert before startInsertPos
if(startInsertPos->start > newInterval.end){
intervals.insert(startInsertPos,newInterval);//insert in the position startInserPos
}
//case2: insert after endInsertPos
else if(endInsertPos->end < newInterval.start){
intervals.insert(endInsertPos+,newInterval);//insert in the position endInsertPos+1
}
//case3: merge
else{
startInsertPos->start = min(newInterval.start, startInsertPos->start);
startInsertPos->end = max(newInterval.end, endInsertPos->end);
intervals.erase(startInsertPos+,endInsertPos+);//erase the elem from startInserPos+1 to endInsertPos
}
return intervals;