Write a program to solve a Sudoku puzzle by filling the empty cells.
Given the array nums after the possible rotation and an integer target, return the index of target if it is in nums, or -1 if it is not in nums.
Given an array of integers nums, find the next permutation of nums.
You are given a string s and an array of strings words. All the strings of words are of the same length. Return the starting indices of all the concatenated substrings in s. You can return the answer in any order.
Given two integers dividend and divisor, divide two integers without using multiplication, division, and mod operator. Return the quotient after dividing dividend by divisor.
Given two strings needle and haystack, return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Given an integer array nums and an integer val, remove all occurrences of val in nums in-place. The relative order of the elements may be changed.
Given the head of a linked list, reverse the nodes of the list k at a time, and return the modified list.
You are given the heads of two sorted linked lists list1 and list2. Merge the two lists in a one sorted list. The list should be made by splicing together the nodes of the first two lists. Return the head of the merged linked list.
You are climbing a staircase. It takes n steps to reach the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?
Given the head of a singly linked list, reverse the list, and return the reversed list.
There is a singly-linked list head and we want to delete a node node in it. Delete the given node
Given an integer num, repeatedly add all its digits until the result has only one digit, and return it.
Given n, the number of stones in the heap, return true if you can win the game assuming both you and your friend play optimally, otherwise return false.
Given an input string s and a pattern p, implement regular expression matching with support for ‘.’ and ‘*’ where ‘.’ Matches any single character and ‘*’ Matches zero or more of the preceding element.