LC 252 - Meeting Rooms

Question

Given an array of meeting time intervals where intervals[i] = [starti, endi], determine if a person could attend all meetings.

Example 1:

Input: intervals = [[0,30],[5,10],[15,20]]
Output: false

Example 2:

Input: intervals = [[7,10],[2,4]]
Output: true

Constraints:

• 0 <= intervals.length <= 104
• intervals[i].length == 2
• 0 <= starti < endi <= 106

Links

Question here and solution here

Solution

concept

This question used the same concept from 435. Non-overlapping Intervals to check for overlapping intervals.

code

class Solution:
    def canAttendMeetings(self, intervals: List[List[int]]) -> bool:
        if not intervals:
            return True

        intervals.sort()
        prev_end = intervals[0][1]

        for start, end in intervals[1:]:
            if start < prev_end:
                return False
            else:
                prev_end = end

        return True
        
class NeetSolution:
    def canAttendMeetings(self, intervals: List[List[int]]) -> bool:
        intervals.sort(key=lambda i: i[0])

        for i in range(1, len(intervals)):
            i1 = intervals[i - 1]
            i2 = intervals[i]

            if i1[1] > i2[0]:
                return False
        return True

Complexity

time: $O(n \log n)$
space: $O(n)$