Given a set of distinct integers, return all possible subsets. Notice Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. Example If S = [1,2,3], a solution is: [ [3], [1], [2], [1,2,3], [1,3], […

CF895C: Square Subsets && [BZOJ2844]albus就是要第一个出场 这两道题很类似,都是线性基的计数问题,解题的核心思想也一样. CF895C Square Subsets 题目链接 题意 给定\(n\)个数,求多少种选数方案使得选出来的数乘积为完全平方数.\(n\leq 100000,a_i\leq70\). 完全平方数的本质就是每个质因子的次数为偶数. 所以我们将每一个数唯一分解,然后记录每个质因子的奇偶状态,就得到了一个个01串.问题就变成了有多少个集…

2. Add Two Numbers[medium] You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. You…

92. Reverse Linked List II[Medium] Reverse a linked list from position m to n. Do it in-place and in one-pass. For example:Given 1->2->3->4->5->NULL, m = 2 and n = 4, return 1->4->3->2->5->NULL. Note:Given m, n satisfy the fo…

82. Remove Duplicates from Sorted List II[Medium] Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. For example,Given 1->2->3->3->4->4->5, return 1->2->5…

61. Search for a Range[medium] Given a sorted array of n integers, find the starting and ending position of a given target value. If the target is not found in the array, return [-1, -1]. Have you met this question in a real interview? Yes Example Gi…

62. Search in Rotated Sorted Array[medium] Suppose a sorted array 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 given a target value to search. If found in the array return its index, ot…

74. First Bad Version [medium] The code base version is an integer start from 1 to n. One day, someone committed a bad version in the code case, so it caused this version and the following versions are all failed in the unit tests. Find the first bad…

75. Find Peak Element [medium] There is an integer array which has the following features: The numbers in adjacent positions are different. A[0] < A[1] && A[A.length - 2] > A[A.length - 1]. We define a position P is a peek if: A[P] > A[P-…

159. Find Minimum in Rotated Sorted Array [medium] Suppose a sorted array 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). Find the minimum element. Notice You may assume no duplicate exists in the…