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[LeetCode] 253. Meeting Rooms II

253. Meeting Rooms II Medium Given an array of meeting time intervals intervals where intervals[i] = [starti, endi], return the minimum number of conference rooms required. Example 1: Input: intervals = [[0,30],[5,10],[15,20]] Output: 2 Example 2: Input: intervals = [[7,10],[2,4]] Output: 1 Constraints: 1

[LeetCode] 23. Merge k Sorted Lists

23. Merge k Sorted Lists Hard You are given an array of k linked-lists lists, each linked-list is sorted in ascending order. Merge all the linked-lists into one sorted linked-list and return it. Example 1: Input: lists = [[1,4,5],[1,3,4],[2,6]] Output: [1,1,2,3,4,4,5,6] Explanation: The linked-lists are: [ 1->4->5, 1->3->4, 2->6 ] merging them into one sorted list: 1->1->2->3->4->4->5->6 Example..

[LeetCode - Biweekly Contest 90]2454. Next Greater Element IV

2454. Next Greater Element IV Hard You are given a 0-indexed array of non-negative integers nums. For each integer in nums, you must find its respective second greater integer. The second greater integer of nums[i] is nums[j] such that: j > i nums[j] > nums[i] There exists exactly one index k such that nums[k] > nums[i] and i < k < j. If there is no such nums[j], the second greater integer is co..