leetcode20: 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> &ints, Interval newInterval) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<Interval> intervals( ints);
                
        int low = newInterval.start;
        int high = newInterval.end;
        
        bool delFlag = false;
        
        for(int i=0; i<intervals.size(); i++) {
            if( intervals[i].start <= low && ( i==intervals.size()-1 || intervals[i+1].start > low ) {
                if( intervals[i].end >= low) {
                    newInterval.start = intervals[i].start;
                    intervals.erase( intervals.begin() + i );
                } 
                delFlag = true;        
            }
            
            if( delFlag) {
                    intervals.erase( intervals.begin() + i);
            }
            
            if( intervals[i].end >= high ) {
                if( intervals[i].start <= high) {
                    newInterval.end = intervals[i].end;
                    intervals.erase( intervals.begin() + i);
                }
                delFlag = false;
                
                intervals.insert( newInterval, i-1);
            }
        }

        return intervals;
    }
};