56. Merge Intervals

Medium (Trung bình) Python 🔗 Xem trên LeetCode

📋 Đề Bài

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

 

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] overlap, 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.

 

Constraints:

  • 1 <= intervals.length <= 104
  • intervals[i].length == 2
  • 0 <= starti <= endi <= 104

🧠 Thuật Toán & Kỹ Thuật

Sorting (Sắp xếp)
⏱️ Thời gian O(n log n)
💾 Không gian O(n)

💻 Lời Giải

Python 0056-merge-intervals.py
class Solution:
    def merge(self, intervals: List[List[int]]) -> List[List[int]]:
        intervals.sort(key = lambda x: x[0])
        ans = []
        
        for start, end in intervals:
            if ans and start <= ans[-1][1]:
                ans[-1][1] = max(ans[-1][1], end)
            else:
                ans.append([start, end])
                
        return ans