leetcode 56. Merge Intervals
Given a collection of intervals, merge all overlapping intervals.
Example 1:
Input: [[1,3],[2,6],[8,10],[15,18]]
Output: [[1,6],[8,10],[15,18]]
Explanation: Since intervals [1,3] and [2,6] overlaps, merge them into [1,6].
Example 2:
Input: [[1,4],[4,5]]
Output: [[1,5]]
Explanation: Intervals [1,4] and [4,5] are considered overlapping.
NOTE: input types have been changed on April 15, 2019. Please reset to default code definition to get new method signature.
思路:先排序,然后依次判断相邻区间是否有覆盖,如果有覆盖,则合并。
class Solution {
public:
vector<vector<int>> merge(vector<vector<int>>& intervals) {
vector<vector<int>> res;
int n=intervals.size();
if(n<=1)return intervals;
sort(intervals.begin(), intervals.end(), [](vector<int> a, vector<int> b){return a[0]<b[0];});
res.push_back(intervals[0]);
for(int i=1;i<n;i++){
if(intervals[i][0]<=res.back()[1])
res.back()[1]=max(res.back()[1],intervals[i][1]);
else
res.push_back(intervals[i]);
}
return res;
}
};