Determine if a 9x9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: Each row must contain…
Given a sorted array and a target value, return the index if the target is found. If not, return the…
Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., [0,1,2,4,5,6,7] might become [4,5,6,7,0,1,2]). You are…
Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not possible, it…
Given an array nums and a value val, remove all instances of that value in-place and return the new length. Do not allocate extra space…
Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new length. Do not allocate extra…
Given a linked list, swap every two adjacent nodes and return its head. You may not modify the values in the list's nodes,…
Merge two sorted linked lists and return it as a new sorted list. The new list should be made by splicing together…
Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. An input string is valid if:…
Given a linked list, remove the n-th node from the end of list and return its head. Example: Given linked list:…
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