recursion

问题 I have been working on generating all possible submodels for a biological problem. I have a working recursion for generating a big list of all the submodels I want. However, the lists get unmanageably large pretty fast (N=12 is just possible in the example below, N>12 uses too much memory). So I wanted to convert it to a generator function using yield instead, but I'm stuck. My working recursive function looks like this: def submodel_list(result, pat, current, maxn): ''' result is a list to

问题 I have been working on generating all possible submodels for a biological problem. I have a working recursion for generating a big list of all the submodels I want. However, the lists get unmanageably large pretty fast (N=12 is just possible in the example below, N>12 uses too much memory). So I wanted to convert it to a generator function using yield instead, but I'm stuck. My working recursive function looks like this: def submodel_list(result, pat, current, maxn): ''' result is a list to

问题 I'm using a canvas object inside my component to generate a chart. In order for it animate i'm calling the method recursively. I keep getting an error saying that the method is not defined. Not sure how I need to structure it. any assistance appreciated. // Animate function protected animate(draw_to) { // Clear off the canvas this.ctx.clearRect(0, 0, this.width, this.height); // Start over this.ctx.beginPath(); // arc(x, y, radius, startAngle, endAngle, anticlockwise) // Re-draw from the very

问题 I'm trying to implement DFS with recursion using the following code, public static void dfs(int i, int[][] mat, boolean [] visited){ visited[i] = true; // Mark node as "visited" System.out.print(i + "\t"); for ( int j = 0; j < visited.length; j++ ){ if ( mat[i][j] ==1 && !visited[j] ){ dfs(j, mat, visited); // Visit node } } } I have a matrix and an array for tracking visited nodes, // adjacency matrix for uni-directional graph int [][] arr = { // 1 2 3 4 5 6 7 8 9 10 { 0, 1, 1, 1, 0, 0, 0, 0

问题 Have a look at the following code from here. It's about preserving circular references in a datacontract (object model, object graph, domain model) when serializing in wcf. class ReferencePreservingDataContractSerializerOperationBehavior :DataContractSerializerOperationBehavior { public ReferencePreservingDataContractSerializerOperationBehavior( OperationDescription operationDescription) : base(operationDescription) { } public override XmlObjectSerializer CreateSerializer( Type type, string

问题 My boss has given me a single table. Related_Items_Table Item | Accessory --------------------- TV | Antennae TV | Power Cord TV | Remote Laptop | Power Cord Laptop | Carrying Case Camera | Carrying Case Camera | Lens iPod | Headphones The best way to describe what my boss wants for results is to walk through the process. The user searches for TV. TV is found and the accessories for TV are Antennae, Power Cord & Remote. The accessories Antennae, Power Cord & Remote are now used to find other

问题 I asked a question earlier about aggregating quantities along a graph. The two answers provided worked well, but now I am trying to extend the Cypher query it to a graph of variable depth. To summarize we start of with a bunch of leaf stores which all are associated with a particular supplier, which is a property on the Store node. Inventory is then moved along to other stores and the proportion from each supplier corresponds to their contribution to the original store. So for node B02 , S2

问题 Given the following function: Function f(n,m) if n == 0 or m == 0: return 1 return f(n-1, m) + f(n, m-1) What's the runtime compexity of f ? I understand how to do it quick and dirty, but how to properly characterize it? Is it O(2^(m*n)) ? 回答1: This is an instance of Pascal's triangle: every element is the sum of the two elements just above it, the sides being all ones. So f(n, m) = (n + m)! / (n! . m!) . Now to know the number of calls to f required to compute f(n, m) , you can construct a

问题 I am trying to write an iterator for a hierarchy of classes that collectively make up the components of a song. All classes are implementations of the abstract MusicComponent base class and inherit a getChildren() function. The abstract MusicTime subclass knows the actual note/chord to play, and all its implementations (e.g. quaver, crotchet) return null for getChildren() . The other components are MusicComponent which holds a collection of MusicTimes e.g. a bar at a time, and Section which

问题 I am trying to write an iterator for a hierarchy of classes that collectively make up the components of a song. All classes are implementations of the abstract MusicComponent base class and inherit a getChildren() function. The abstract MusicTime subclass knows the actual note/chord to play, and all its implementations (e.g. quaver, crotchet) return null for getChildren() . The other components are MusicComponent which holds a collection of MusicTimes e.g. a bar at a time, and Section which