[leetcode]Insert Interval

/**

 * 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> pre;

        vector<Interval> post;

        

        int low = newInterval.start;

        int high = newInterval.end;

        

        for(int i = 0; i < intervals.size(); i++){

            if(intervals[i].end < low){

                pre.push_back(intervals[i]);

            }

            if(intervals[i].start > high){

                post.push_back(intervals[i]);

            }

        }

        

        int p;

        

        if(intervals.empty() || pre.size() == intervals.size()){

            p = low;

        }else{

            p = min(low, intervals[pre.size()].start);

        }

        

        int q;

        if(intervals.empty() || post.size() == intervals.size()){

            q = high;

        }else{

            q = max(high, intervals[intervals.size()-1-post.size()].end);

        }

        

        pre.push_back(Interval(p,q));

        pre.insert(pre.end(), post.begin(), post.end());

        

        return pre;

        

    }

};