LeetCode-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:
    bool compare(Interval& i1,Interval&i2){
        if(i1.start<i2.start)return true;
        else if(i1.start==i2.start){
            return i1.end<i2.end;
        }
        else return false;
    }
    vector<Interval> insert(vector<Interval> &intervals, Interval newInterval) {
        vector<Interval> ret;
        bool put=false;
        for(int i=0;i<intervals.size();i++){
            if(intervals[i].end<newInterval.start||intervals[i].start>newInterval.end){
                if(!put&&intervals[i].start>newInterval.end){
                    ret.push_back(newInterval);
                    put=true;
                }
                ret.push_back(intervals[i]);
            }
            else{
                newInterval.start=min(newInterval.start,intervals[i].start);
                newInterval.end=max(newInterval.end,intervals[i].end);
            }
        }
        if(!put)ret.push_back(newInterval);
        return ret;
    }
};