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 …
Monthly Archives: October 2016
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 …
Leetcode 325: Maximum Size Subarray Sum Equals k
325. Maximum Size Subarray Sum Equals k Total Accepted: 13137 Total Submissions: 31728 Difficulty: Medium Contributors: Admin Given an array nums and a target value k, find the maximum length of a subarray that sums to k. If there isn’t one, return 0 instead. Note:The sum of the entire nums array is guaranteed to fit …
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Leetcode 161: One Edit Distance
161. One Edit Distance Total Accepted: 20350 Total Submissions: 68060 Difficulty: Medium Contributors: Admin Given two strings S and T, determine if they are both one edit distance apart. Code class Solution(object): def isOneEditDistance(self, s, t): “”” :type s: str :type t: str :rtype: bool “”” for idx, (chr_s, chr_t) in enumerate(zip(s, …
Leetcode 191: Number of 1 Bits
191. Number of 1 Bits Total Accepted: 119474 Total Submissions: 312895 Difficulty: Easy Contributors: Admin Write a function that takes an unsigned integer and returns the number of ’1′ bits it has (also known as the Hamming weight). For example, the 32-bit integer ’11′ has binary representation 00000000000000000000000000001011, so the function should return 3. …
Leetcode 285: Inorder Successor in BST
285. Inorder Successor in BST Total Accepted: 17302 Total Submissions: 47674 Difficulty: Medium Contributors: Admin Given a binary search tree and a node in it, find the in-order successor of that node in the BST. Note: If the given node has no in-order successor in the tree, return null. Code # Definition for a …
Leetcode 253: Meeting Rooms II
253. Meeting Rooms II Total Accepted: 20906 Total Submissions: 55624 Difficulty: Medium Contributors: Admin Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],…] (si < ei), find the minimum number of conference rooms required. For example,Given [[0, 30],[5, 10],[15, 20]],return 2. Code # Definition for an interval. # class …