311. Sparse Matrix Multiplication Total Accepted: 13356 Total Submissions: 26970 Difficulty: Medium Contributors: Admin Given two sparse matrices A and B, return the result of AB. You may assume that A‘s column number is equal to B‘s row number. Code from collections import defaultdict class Solution(object): def multiply(self, A, B): “”” :type A: List[List[int]] …
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237. Delete Node in a Linked List Total Accepted: 114749 Total Submissions: 255293 Difficulty: Easy Contributors: Admin Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the …
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117. Populating Next Right Pointers in Each Node II Total Accepted: 74952 Total Submissions: 225622 Difficulty: Hard Contributors: Admin Follow up for problem “Populating Next Right Pointers in Each Node“. What if the given tree could be any binary tree? Would your previous solution still work? Note: You may only use constant extra space. For …
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371. Sum of Two Integers Total Accepted: 42501 Total Submissions: 82322 Difficulty: Easy Contributors: Admin Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -. Example:Given a = 1 and b = 2, return 3. Code class Solution(object): def getSum(self, a, b): “”” …
292. Nim Game Total Accepted: 105850 Total Submissions: 194593 Difficulty: Easy Contributors: Admin You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 stones. The one who removes the last stone will be …
137. Single Number II Total Accepted: 100365 Total Submissions: 253451 Difficulty: Medium Contributors: Admin Given an array of integers, every element appears three times except for one. Find that single one. Note:Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory? Code class Solution(object): def singleNumber(self, nums): “”” …
72. Edit Distance Total Accepted: 71110 Total Submissions: 236049 Difficulty: Hard Contributors: Admin Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.) You have the following 3 operations permitted on a word: a) Insert a characterb) Delete a characterc) …
150. Evaluate Reverse Polish Notation Total Accepted: 76968 Total Submissions: 304324 Difficulty: Medium Contributors: Admin Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, /. Each operand may be an integer or another expression. Some examples: [“2”, “1”, “+”, “3”, “*”] -> ((2 + 1) * 3) …
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138. Copy List with Random Pointer Total Accepted: 81110 Total Submissions: 308920 Difficulty: Hard Contributors: Admin A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. Code # Definition for singly-linked list …
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136. Single Number Total Accepted: 167202 Total Submissions: 320990 Difficulty: Easy Contributors: Admin Given an array of integers, every element appears twice except for one. Find that single one. Note:Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory? Code class Solution(object): def singleNumber(self, nums): “”” :type nums: …