LeetCode-in-All
56. Merge Intervals
Medium
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] 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.
Constraints:
1 <= intervals.length <= 104intervals[i].length == 20 <= starti <= endi <= 104
Solution
class Solution {
/**
* @param Integer[][] $intervals
* @return Integer[][]
*/
public function merge($intervals) {
array_multisort($intervals);
$res = [$intervals[0]];
$k = 0;
for ($i = 1; $i < count($intervals); $i++) {
$start = $intervals[$i][0];
$end = $intervals[$i][1];
$last_interv = end($res);
if ($start <= $last_interv[1]) {
$res[$k] = [$last_interv[0], max($end, $last_interv[1])];
} else {
$res[] = $intervals[$i];
$k++;
}
}
return $res;
}
}