題目：

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.

例子:

Example 1:

Input: intervals = [[1,3],[6,9]], newInterval = [2,5]
Output: [[1,5],[6,9]]

Example 2:

Input: intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]
Output: [[1,2],[3,10],[12,16]]
Explanation: Because the new interval [4,8] overlaps with [3,5],[6,7],[8,10].

問題解析：

給定間隔陣列，和需要插入的間隔，將間隔插入到陣列中，返回新陣列。

連結：

思路標籤

前和後比較、後與前比較

解答：

• 題目其實不難，關鍵是理清楚什麼時候更新插入的新節點。

/**
 * 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) {
        vector<Interval> ret;

        auto iter = intervals.begin();
        while(iter != intervals.end() && iter->end < newInterval.start){
            ret.push_back(*iter);
            iter++;
        }

        while
 
(iter != intervals.end() && iter->start <= newInterval.end){
            newInterval.start = min(newInterval.start, iter->start);
            newInterval.end = max(newInterval.end, iter->end);
            iter++;
        }

        ret.push_back(newInterval);

        while(iter != intervals.end()){
            ret.push_back(*iter);
            iter++;
        }

        return ret;
    }
};