21. Merge Two Sorted Lists Total Accepted: 167826 Total Submissions: 448665 Difficulty: Easy Contributors: Admin Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists. Code # Definition for singly-linked list. # class ListNode(object): # def __init__(self, …
Category Archives: leetcode
Leetcode 14: Longest Common Prefix
14. Longest Common Prefix Total Accepted: 131998 Total Submissions: 438812 Difficulty: Easy Contributors: Admin Write a function to find the longest common prefix string amongst an array of strings. Code class Solution(object): def longestCommonPrefix(self, strs): “”” :type strs: List[str] :rtype: str “”” if not strs: return “” prefix = “” for k in xrange(len(strs[0])): …
Leetcode 24: Swap Nodes in Pairs
24. Swap Nodes in Pairs Total Accepted: 130373 Total Submissions: 354429 Difficulty: Easy Contributors: Admin Given a linked list, swap every two adjacent nodes and return its head. For example,Given 1->2->3->4, you should return the list as 2->1->4->3. Your algorithm should use only constant space. You may not modify the values in the list, only …
Leetcode 18: 4Sum
18. 4Sum Total Accepted: 92730 Total Submissions: 367805 Difficulty: Medium Contributors: Admin Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target. Note: The …
Leetcode 19: Remove Nth Node From End of List
19. Remove Nth Node From End of List Total Accepted: 140954 Total Submissions: 445848 Difficulty: Easy Contributors: Admin Given a linked list, remove the nth node from the end of list and return its head. For example, Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from the end, the linked …
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Leetcode 200: Number of Islands
200. Number of Islands Total Accepted: 71131 Total Submissions: 228449 Difficulty: Medium Contributors: Admin Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid …
Leetcode 75: Sort Colors
75. Sort Colors Total Accepted: 125210 Total Submissions: 345796 Difficulty: Medium Contributors: Admin Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue. Here, we will use the integers 0, 1, and 2 …
Radix Sort
A post to review RadixSort. The idea is to Code class RadixSort(): def sort(self, nums): max_num = max(nums) exp = 1 while max_num / exp: nums = self.count_sort(nums, exp) exp = exp * 10 return nums def count_sort(self, nums, exp): # how many numbers have 0~9 for the current position digit_counts = [0] * …
Leetcode 169: Majority Element
169. Majority Element Total Accepted: 152482 Total Submissions: 346405 Difficulty: Easy Contributors: Admin Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. You may assume that the array is non-empty and the majority element always exist in the array. …
Leetcode 277: Find the Celebrity
277. Find the Celebrity Total Accepted: 15126 Total Submissions: 42620 Difficulty: Medium Contributors: Admin Suppose you are at a party with n people (labeled from 0 to n – 1) and among them, there may exist one celebrity. The definition of a celebrity is that all the other n – 1 people know him/her but …