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252. Meeting Rooms πŸ”’

Description

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

Solutions

Solution 1

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class Solution:
    def canAttendMeetings(self, intervals: List[List[int]]) -> bool:
        intervals.sort()
        return all(a[1] <= b[0] for a, b in pairwise(intervals))

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class Solution {
    public boolean canAttendMeetings(int[][] intervals) {
        Arrays.sort(intervals, (a, b) -> a[0] - b[0]);
        for (int i = 1; i < intervals.length; ++i) {
            var a = intervals[i - 1];
            var b = intervals[i];
            if (a[1] > b[0]) {
                return false;
            }
        }
        return true;
    }
}

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class Solution {
public:
    bool canAttendMeetings(vector<vector<int>>& intervals) {
        sort(intervals.begin(), intervals.end(), [](const vector<int>& a, const vector<int>& b) {
            return a[0] < b[0];
        });
        for (int i = 1; i < intervals.size(); ++i) {
            if (intervals[i][0] < intervals[i - 1][1]) {
                return false;
            }
        }
        return true;
    }
};

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func canAttendMeetings(intervals [][]int) bool {
    sort.Slice(intervals, func(i, j int) bool {
        return intervals[i][0] < intervals[j][0]
    })
    for i := 1; i < len(intervals); i++ {
        if intervals[i][0] < intervals[i-1][1] {
            return false
        }
    }
    return true
}

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function canAttendMeetings(intervals: number[][]): boolean {
    intervals.sort((a, b) => a[0] - b[0]);
    for (let i = 1; i < intervals.length; ++i) {
        if (intervals[i][0] < intervals[i - 1][1]) {
            return false;
        }
    }
    return true;
}

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impl Solution {
    #[allow(dead_code)]
    pub fn can_attend_meetings(intervals: Vec<Vec<i32>>) -> bool {
        if intervals.len() == 1 {
            return true;
        }

        let mut intervals = intervals;

        // Sort the intervals vector
        intervals.sort_by(|lhs, rhs| lhs[0].cmp(&rhs[0]));

        let mut end = -1;

        // Begin traverse
        for p in &intervals {
            if end == -1 {
                // This is the first pair
                end = p[1];
                continue;
            }
            if p[0] < end {
                return false;
            }
            end = p[1];
        }

        true
    }
}

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