• [leetcode] a series of derivative problems of binary tree traversal


    Non recursive traversal Non recursive preorder traversal Iterative traversal is assisted by stack, which stores the parent node to traverse the current subtree, and then traverse the sibling subtree of the current subtree. The idea is clear. Just pay attention to the judgment conditions of the cycle. class Solution { public: vector<int> preorderTraversal(TreeNode* root) { […]

  • Game theory Nim Game 2 (hh2048 question sheet)


    [main idea of the title]: Simple nim# output the number of schemes in the first step [idea]: The NIM part is an ordinary NIM. The difficulty is to output the number of schemes in the first step. Suppose x is the value after XOR. x = a1 ^a2 ^ a3 ^ a4 ^ a5 。 […]

  • As a software technician, what is the difference between China’s industrial software?


    “China’s industrial software” is an old topic,The ideal state is always new, but it is still not optimistic about the development of industrial software。 As a technician with more than 10 years of development experience, talk about this macro topic to face up to the future development. Recently, I communicated with a boss who made […]

  • Best cattle fence and search section


    Because the two questions are similar, they are combined into one question solution ———– inscription Best cattle fence Idea: Dichotomous answerThe answer is the average How to check whether the answer meets the meaning of the question,Judge whether an interval satisfying the meaning of the question is > = this average valueGenerally, you can subtract […]

  • Experience determines the solution


    When the “Tao” family provides the “Tao” thinking, it just provides an operation model for people, just like a robot, which is a thinking model for people. Under this thinking model, it needs continuous input of information and more changes to make this model run better. Or provide specific running programs under this model. The […]

  • Sql45 questions


    1、 Data preparation Exercise data data sheet–1. Student form (SID, sname, sage, ssex)Sid student number, sname student name, sage date of birth, ssex student gender–2. Course (CID, CNAME, TID)CID course number, CNAME course name, TID teacher number–3. Teacher (TID, tname)TID teacher number, tname teacher name–4. Score sheet SC (SID, CID, score)Sid student number, CID course […]

  • [typescript] list algorithm question type and method summary


    The linked list questions have been brushed about 20 times, and some rules have been summarized and shared with you Problem solving ideas The main ideas are recursion and iteration, which also include some skilled operations, such as fast and slow pointers. These problem-solving ideas summarized should not be a problem for most linked list […]

  • Topic test four graph theory (time limited) a – Networking


    subjectYou are assigned to design network connections between certain points in a wide area. You are given a set of points in the area, and a set of possible routes for the cables that may connect pairs of points. For each possible route between two points, you are given the length of the cable that […]

  • 10 exhaustive penetration test 02


    After many days, I finally finished the master’s class in October in one day. At present, the idea of exhaustive is to find one or two points for exhaustive, and then use tools to test constantly Although master Yue introduced several blasting test methods I didn’t know before And test ideas. The previous understanding of […]

  • Troubleshooting ideas of feignclient annotation attribute configuration not taking effect


    Troubleshooting ideas of feignclient annotation attribute configuration not taking effect Problem background We know that “if you need to customize a single feign configuration, the class of the @ configuration annotation of feign cannot overlap with the package of @ componentscan. In this way, if the package overlaps, all feign clients will use the configuration”. […]

  • System administrator (construct a diagram with a cut point)


    Title Link Connect V to all points (n-1 edges) For a point R connected by the cut point v, after removing the cut point v, there are n-1 points left, in which n-2 points other than R are interconnected (up to (n-2) (n-3) / 2 edges), Then these n-2 points are not connected with R, […]

  • Qduoj fake check-in question (quick reading)


    Title Link:click here #include<iostream> #include<algorithm> #include<string> #include<cstdio> #include<cstring> #include<cmath> #include<stack> #include<queue> using namespace std; typedef long long ll; const int MOD = 15; const int INF = 0x3f3f3f3f; const double PI = acos(-1.0); const int maxn = 1000010; int a[maxn]; inline int _read() { char ch = getchar(); int sum = 0; while (!(ch >= […]