Given a chemical formula (given as a string), return the count of each atom. An atomic element always starts with an uppercase character, then zero or more lowercase letters, representing the name. 1 or more digits representing the count of that elem…

原题链接在这里:https://leetcode.com/problems/number-of-atoms/description/ 题目: Given a chemical formula (given as a string), return the count of each atom. An atomic element always starts with an uppercase character, then zero or more lowercase letters, repr…

leetcode:Number of 1 Bits 代码均测试通过! 1.Number of 1 Bits 本题收获: 1.Hamming weight:即二进制中1的个数 2.n &= (n-1)[n = n & (n-1)]的用处 题目: Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight).…

LeetCode--Number Complement Question Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation. Note: The given integer is guaranteed to fit within the range of a 32-bit signed in…

LeetCode--Number of Boomerangs Question Given n points in the plane that are all pairwise distinct, a "boomerang" is a tuple of points (i, j, k) such that the distance between i and j equals the distance between i and k (the order of the tuple m…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址: https://leetcode.com/problems/number-of-atoms/description/ 题目描述: Given a chemical formula (given as a string), return the count of each atom. An atomic element always starts with an upperc…

题目如下: 解题思路:我用的是递归的方法,每次找出与第一个')'匹配的'('计算atom的数量后去除括号,只到分子式中没有括号为止.例如 "K4(ON(SO3)2)2" -> "K4(ONS2O6)2" -> "K4O2N2S4O12".接下来再对分子式进行分割,得出每个atom的数量后排序即可.原理很简单,代码写得很乱,仅供参考. 代码如下: class Solution(object): def recursive(self,fo…

Given n points in the plane that are all pairwise distinct, a "boomerang" is a tuple of points (i, j, k) such that the distance between i and j equals the distance between i and k (the order of the tuple matters). Find the number of boomerangs.…

Count the number of segments in a string, where a segment is defined to be a contiguous sequence of non-space characters. Please note that the string does not contain any non-printable characters. Example: Input: "Hello, my name is John" Output:…

Given n nodes labeled from 0 to n - 1 and a list of undirected edges (each edge is a pair of nodes), write a function to find the number of connected components in an undirected graph. Example 1: 0          3 |          | 1 --- 2    4 Given n = 5 and…