The Algorithm Design Manual by Steve Skiena isn’t exactly a barrel of laughs, but it’s relatively light on the deeper mathematics and contains lots of what he calls “War Stories”, which are illustrative examples from real world situations where algorithm work really paid off (or, sometimes, totally failed). He’s also got his audio and video … Read more
When you want a queue, use a PriorityQueue. When you want a Set, use a TreeSet. A TreeSet has unique elements, and doesn’t offer the API of a Queue. A Queue doesn’t offer the API of a Set, and allows multiple equal elements.
There are probably a lot of different (and good) answers, but in my humble opinion, the common characteristics of probabilistic data structures is that they provide you with approximate, not precise answer. How many items are here? About 1523425 with probability of 99% Update: Quick search produced link to decent article on the issue: Probabilistic … Read more
It has no special meaning in a list or dictionary, but can be useful when using source code change management tools, see below. Non-empty tuples are defined by using a comma between elements, the parentheses are optional and only required in contexts where the comma could have a different meaning. Because the comma defines the … Read more
Well the pair can’t exist if the key doesn’t exist… so fetch the value associated with the key, and check whether that’s the value you were looking for. So for example: // Could be generic of course, but let’s keep things simple… public bool ContainsKeyValue(Dictionary<string, int> dictionary, string expectedKey, int expectedValue) { int actualValue; if … Read more
Another way of solving this is using Quickselect. This should give you a total average time complexity of O(n). Consider this: Find the kth largest number x using Quickselect (O(n)) Iterate through the array again (or just through the right-side partition) (O(n)) and save all elements ≥ x Return your saved elements (If there are … Read more
You could always just use Data.Sequence. Alternatively, a well-known implementation of a purely functional queue is to use two lists. One for enqueue and another for dequeue. Enqueue would simply cons with the enqueue list. Dequeue takes the head of the dequeue list. When the dequeue list is shorter than the enqueue list, refill it … Read more
The erase() method returns a new (valid) iterator that points to the next element after the deleted one. You can use this iterator to continue with the loop: std::vector<std::string>::iterator iter; for (iter = m_vPaths.begin(); iter != m_vPaths.end(); ) { if (::DeleteFile(iter->c_str())) iter = m_vPaths.erase(iter); else ++iter; }
Tuples are available since .NET4.0 and support generics: Tuple<string, int> t = new Tuple<string, int>(“Hello”, 4); In previous versions you can use System.Collections.Generic.KeyValuePair<K, V> or a solution like the following: public class Pair<T, U> { public Pair() { } public Pair(T first, U second) { this.First = first; this.Second = second; } public T First … Read more
I learned that depth and height are properties of a node: The depth of a node is the number of edges from the node to the tree’s root node.A root node will have a depth of 0. The height of a node is the number of edges on the longest path from the node to … Read more