Given a collection of intervals, merge all overlapping intervals.
Example 1:
Input: intervals = [[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: intervals = [[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.
Constraints:
intervals[i][0] <= intervals[i][1]
public class Solution {
public int[][] Merge(int[][] intervals) {
if(intervals.Length==0){
return intervals;
}
Array.Sort(intervals, (a, b) => { return a[0] - b[0]; });
var res = new List<int[]>();
int start = intervals[0][0];
int end = intervals[0][1];
for(int i=1;i<intervals.Length;i++){
if(end>=intervals[i][0] && end <= intervals[i][1]){
end = intervals[i][1];
}
else if(end < intervals[i][0]){
res.Add(new int[]{start,end});
start = intervals[i][0];
end = intervals[i][1];
}
}
res.Add(new int[]{start, end});
return res.ToArray();
}
}Time Complexity: O(nlogn)
Space Complexity: O(n)
