• JavaScript graphic example: Hilbert curve


    In 1891, German mathematician David Hilbert constructed a kind of curve. First, he divided a square into four small squares, starting from the center of the square in the northwest corner, going south to the center of the square in the southwest, then east to the center of the square in the southeast corner, and […]

  • Understanding topological ordering


    preface Topological sort, also known as topological order, is a bit confusing, because topological sort is not a pure sort algorithm, it is only for the purpose of sortingA class of GraphsTo find a linear order that can be executed. This algorithm sounds like a big one. Today’s interviews are also very popular. For example, […]

  • Application of graph topological ordering and critical path solving


    1. Topological sorting 1.1 introduction to topological sorting There are ⼀ digraphs that represent ⼯ processes, in which ⽤ vertices represent activities, and arcs represent the priority relationship between activities. In this way, digraphs represent ⽹ activities for vertices, which is called activity on vertex networkAs shown in Figure 1.1.1 below:The finite set of activities […]

  • UE4 / Unity: basic elements of map drawing — surface and volume


    preface Drawing map basic element line based on UE4 / Unity (Part 1) Drawing map basic element line based on UE4 / Unity (Part 2) After drawing lines on the map, the next step is to draw faces and volumes As one of the basic elements of map rendering, surface can represent all kinds of […]

  • [grid compression evaluation] meshquan, meshopt, Draco


    catalog introduceKHR_mesh_quantizationandEXT_meshopt_compression Use, usage Performance (compression, loading, parsing) Available (scene, range) shortcoming Guess the future direction of improvement summary introduce Gltf compression, estimates all knowDracoBecause of the adaptation of gltfloader to applets, we found that there are many other compression extensions, such asKHR_mesh_quantizationandEXT_meshopt_compression KHR_mesh_quantization Quantification, also known as vectorization, is to express the data represented […]

  • Picture (exercise class)


    An undirected connected graph with 8 nodes has at least (7) edges Spanning tree is the least edge of undirected connected graph. An undirected graph with n vertices and N-1 edges is called a spanning tree. The spanning tree with the smallest weight is the smallest spanning tree. When using adjacency table to represent graph […]

  • Picture (exercise class 2)


    Which of the following four digraphs is not strongly connected. ( B) First, we define what is a strongly connected graph: a directed graph is said to be strongly connected if every node has a path to any other node.Judgment method: take any node s of the digraph g, start the depth first search from s, […]

  • Seven steps to master Apache spark 2.0 (2)


    It was popularized in the last articleSparkLet’s continue to study its core structure and easy-to-use API. This video is rich in content and can’t be missed by fan and Qi. Front portal:Seven steps to mastering Apache spark 2.0 (1) 3、 The core structure of Apache spark In order to better understand how the various components […]

  • Depth first search of Graphs


    Depth first search of graphs 1. Push the first vertex into the stack; 2. As long as there are still vertices in the stack, the following operations are performed in the loop: (1) Access the vertex u at the top of the stack; (2) When moving from the currently accessed vertex u to the vertex […]

  • Illustration: what is “diagram”?


    From today on, we begin to introduce the graph related algorithm diagram: what is “graph”? 1. Background As the beginning of graph, let’s look at a classical problem, which is considered to be the origin of graph theory. The problem is based on a real-life example: there are two small islands in the middle of […]

  • Illustration: depth first search and breadth first search


    Graph algorithm Part 2 depth first search and breadth first search and their applications Convention: all graphs involved in this paper are undirected graphs, and digraphs will be involved in later articles 1. Storage method of graph Let’s first review the storage method in the following figure: adjacency matrix and adjacency table. In order to […]

  • Illustration: how to understand “Relaxation” or “Relaxation” in the shortest path?


    This is the fifth article of graph algorithm: illustration: how to understand “Relaxation” or “Relaxation” of the shortest path? The purpose of the shortest path problem is to find the path with the least cost from one vertex to another.Shortest path algorithmIt is widely used to solve various complex problems, such as finding the shortest […]