No.212 - LeetCode[57] Insert Interval - 已排序区间合并新区间

核心思想，额外空间，分三段处理，时间复杂度O(N)

/*
 * @lc app=leetcode id=57 lang=cpp
 *
 * [57] Insert Interval
 */

// @lc code=start
class Solution {
public:
    vector<vector<int>> insert(vector<vector<int>>& intervals, vector<int>& newInterval) {
        vector<vector<int>> ans;
        int N = intervals.size();
        int loc = 0;
        while(loc < N && newInterval[0] > intervals[loc][1]){
            ans.push_back(intervals[loc++]);
        }
        while(loc < N && newInterval[1] >= intervals[loc][0]){
            newInterval[0] = min(newInterval[0], intervals[loc][0]);
            newInterval[1] = max(newInterval[1], intervals[loc++][1]);
        }
        ans.push_back(newInterval);
        while(loc < N){
            ans.push_back(intervals[loc++]);
        }
        return ans;
    }
};
// @lc code=end