leetcode_question_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) {

        // Start typing your C/C++ solution below

        // DO NOT write int main() function

        vector<Interval>::iterator itstart=intervals.begin();

    	for(; itstart!=intervals.end(); ++itstart)

			if((*itstart).start <= newInterval.start && newInterval.start <= (*itstart).end)

				break;

		vector<Interval>::iterator itend=intervals.begin();

		for(; itend!=intervals.end(); ++itend)

    		if((*itend).start <= newInterval.end && newInterval.end <= (*itend).end)

				break;

		if(itstart!=intervals.end() && itend!=intervals.end())

		{

			if(itstart != itend)

			{

				(*itstart).end = (*itend).end;

                int tmp = (*itstart).end;

    			itstart++;

				while(itstart != intervals.end())

                if((*itstart).start <= tmp)

                    itstart = intervals.erase(itstart);

                else break;

			}

			return intervals;

		}else if(itstart==intervals.end() && itend!=intervals.end())

		{

			(*itend).start = newInterval.start;

            int tmp1 = (*itend).start;

            int tmp2 = (*itend).end;

            itstart = intervals.begin();

    		while((*itstart).start != tmp1 && (*itstart).end != tmp2)

                if((*itstart).start >= tmp1 && (*itstart).end <= tmp2)

                     itstart = intervals.erase(itstart);

                else ++itstart;

			return intervals;

		}else if(itstart!=intervals.end() && itend==intervals.end())

		{

			(*itstart).end = newInterval.end;

            int tmp = newInterval.end;

            ++itstart;

			while(itstart != intervals.end())

            if((*itstart).start < tmp)

                itstart = intervals.erase(itstart);

            else break;

			return intervals;

		}else{

			vector<Interval>::iterator it=intervals.begin();

			for(; it!=intervals.end(); ++it)

				if((*it).start > newInterval.start)

					break;

			//--it;

			vector<Interval>::iterator it1 = intervals.insert(it,newInterval);

            while(it1 != intervals.end())

            {  

                if((*it1).end < newInterval.end)

                it1 = intervals.erase(it1);

    			else

                it1++;

            }

			return intervals;

		}

    }

};