leetcode || 57、Insert Interval

problem:

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].

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Array Sort

题意：和56题类似，只是要插入一个新的区间

thinking:

如果采用multimap<int, int>排序，只需将newInterval插入到multimap中即可，具体参考56题解法

code:

class Solution {
public:
    vector<Interval> insert(vector<Interval> &intervals, Interval newInterval) {
        vector<Interval> ret;
        multimap<int,int> map_intervals;
        if(intervals.size()==0) //边界条件有点变化
        {
             ret.push_back(newInterval);
             return ret;
        }
        for(vector<Interval>::iterator it=intervals.begin();it!=intervals.end();it++)
            map_intervals.insert(make_pair((*it).start,(*it).end));
        map_intervals.insert(make_pair(newInterval.start,newInterval.end));//就加了这一行代码
        multimap<int, int>::iterator p=map_intervals.begin();
        Interval tmp(p->first,p->second);
        for(multimap<int, int>::iterator k=++p;k!=map_intervals.end();k++)
        {
            if(k->first<=tmp.end)
                tmp.end=max(tmp.end,k->second);
            else
            {
                ret.push_back(tmp);
                tmp.start=k->first;
                tmp.end=k->second;
            }
        }
        ret.push_back(tmp);
        return ret;

    }
};