[leetcode 215] Kth Largest Element in an Array
Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. Example 1: Input: [3,2,1,5,6,4] and k = 2 Output: 5 Example 2: Input: [3,2,3,1,2,4,5,5,6] and k = 4 Output: 4 Note: You may assume k is always valid, 1 ≤ k ≤ array's length. 문제풀이: - k번째 큰 수를 찾는다. 중복된 수도 존재! - 소팅한 후에 뒤에서 부터 숫자를 찾는다. class Solution { public:..
2020. 11. 4.
[leetcode 128] Longest Consecutive Sequence
Given an unsorted array of integers nums, return the length of the longest consecutive elements sequence. Follow up: Could you implement the O(n) solution? Example 1: Input: nums = [100,4,200,1,3,2] Output: 4 Explanation: The longest consecutive elements sequence is [1, 2, 3, 4]. Therefore its length is 4. Example 2: Input: nums = [0,3,7,2,5,8,4,6,0,1] Output: 9 Constraints: 0
2020. 11. 2.
[leetcode 148] Sort List
Given the head of a linked list, return the list after sorting it in ascending order. Follow up: Can you sort the linked list in O(n logn) time and O(1) memory (i.e. constant space)? Example 1: Input: head = [4,2,1,3] Output: [1,2,3,4] Example 2: Input: head = [-1,5,3,4,0] Output: [-1,0,3,4,5] Example 3: Input: head = [] Output: [] Constraints: The number of nodes in the list is in the range [0,..
2020. 11. 2.
[leetcode 160] Intersection of Two Linked Lists
Write a program to find the node at which the intersection of two singly linked lists begins. For example, the following two linked lists: begin to intersect at node c1. Example 1: Input: intersectVal = 8, listA = [4,1,8,4,5], listB = [5,6,1,8,4,5], skipA = 2, skipB = 3 Output: Reference of the node with value = 8 Input Explanation: The intersected node's value is 8 (note that this must not be 0..
2020. 11. 2.
