LeetCode Insert Interval-优快云博客

本文介绍了一种在已排序的不重叠区间中插入新区间并进行必要合并的算法。通过两个实例展示了如何处理区间重叠的情况，最终得到合并后的区间集合。

题目：

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.

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) {
		vector<Interval> ans;
		vector<Interval>::iterator it = intervals.begin();
		while (it != intervals.end()) {
			if (newInterval.end < it->start) {
				ans.push_back(newInterval);
				ans.insert(ans.end(), it, intervals.end());
				return ans;
			}
			else if (newInterval.start > it->end) {
				ans.push_back(*it);
			}
			else {
				newInterval.start = min(it->start, newInterval.start);
				newInterval.end = max(it->end, newInterval.end);
			}
			it++;
		}
		ans.insert(ans.end(), newInterval);
		return ans;
	}
};