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) {
        int intervalsSize = intervals.size();
        vector<Interval> res;
        if(intervalsSize==0){
            res.push_back(newInterval);
            return res;
        }
        bool isFindStart = false,isFindEnd = false;
        int start = newInterval.start,end = newInterval.end;
        int startIndex = 0,endIndex=0;
        for(int i =0;i<intervalsSize;i++){//查找合并区间的起始和结束位置
            if(!isFindStart){
                if(start >= intervals[i].start && start<=intervals[i].end){
                    isFindStart = true;
                    start = intervals[i].start;
                    startIndex = i;
                }else if(start<intervals[i].start){
                    startIndex = i;
                    isFindStart = true;
                }
            }
         //   cout<<"end="<<end<<",intervals["<<i<<"].start="<<intervals[i].start<<",intervals["<<i<<"].end="<<intervals[i].end<<endl;
            if(!isFindEnd){
                if(end >= intervals[i].start && end<=intervals[i].end ){
                    isFindEnd = true;
                    end = intervals[i].end;
                    endIndex = i;
                }else if(end<intervals[i].start){
                    endIndex = i-1;
                    isFindEnd = true;
                }   
            }
            if(isFindStart && isFindEnd){
                break;
            }
        }
        if(!isFindStart) startIndex = intervalsSize;
        for(int j=0;j<startIndex;j++){
            res.push_back(intervals[j]);
        }
        res.push_back(Interval(start,end));
        if(!isFindEnd) endIndex = intervalsSize-1;
        for(int j=endIndex+1;j<intervalsSize;j++){
            res.push_back(intervals[j]);
        }
        
        return res;
    }
};