sortedlist | 易学教程

A SortedList.IndexOfKey(key) that returns the index of the item where item.key >= key

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问题 SortedList<TKey, TValue>.IndexOfKey(key) returns -1 if key is not in the list. Does this mean I have to implement a binary search myself if I want to find the index of the key in the list that is greater or equal to key ? Or is there something out of the box that I overlooked? I want to get the result in O(log(n)) of course, so please no LINQ iterate and filter magic. (In general, I'd like to have something like Java's NavigableMap functionality, i.e. features like efficient iteration over a

Is there a sorted java collection which handles duplicates?

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问题 I need a collection that behaves something like C++ multimap, but I also need to be able to get elements by a range of keys. 回答1: There is no built-in multimap collection in Java. To solve this you can map to every key a list of values: Map<String, List<String>> , for example. Otherwise there are third-party libraries with implemented multimaps - here is one of them. 回答2: You can look into Google Collections. It has multiple implementations for MultiMap . 回答3: There is a simple hack around

Is there an indexable sorted list in the Java.util package?

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问题 I'm looking for a data structure in the java.util package. I need it to meet the following requirements: The number of elements is (theoretically) unbounded. The elements are sorted in an ascending order. You can get the nth element (fast). You can remove the nth element (fast). I expected to find an indexable skip list, but I didn't. Do they have any data structure which meets the requirements I'v stated? 回答1: There exists no simple data structure that fulfills all your criteria. The only

Why doesn't C# .NET SortedList<T1, T2> actually have ElementAt?

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问题 .NET Documentation for 3.5 Collections.Generic.SortedList In the documentation, it plainly states that "ElementAt" is an extension method on SortedList members. Well, I've got one, declared thusly: private SortedList<int, ChainLink> linksByLevel = new SortedList<int, ChainLink>(); I try to get the last element: ChainLink lastLink = linksByLevel.ElementAt(linksByLevel.Count - 1); The compiler throws the massively helpful message: Error 1 'System.Collections.Generic.SortedList' does not contain

How to find an index at which a new item can be inserted into sorted list and keep it sorted?

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问题 a = 132 b = [0, 10, 30, 60, 100, 150, 210, 280, 340, 480, 530] I want to know that a should be in the 6th position in ordered list b . What's the most pythonic way to do so? 回答1: Use bisect. It's not the most beautiful API, but it's exactly what you need. You'll want to use bisect.bisect , which returns exactly what you want. 回答2: bisect is a module in the Python Standard Library that is perfect for this task. The function bisect in the module bisect will give you the index of the insertion

Why doesn't C# .NET SortedList<T1, T2> actually have ElementAt?

阅读更多关于 Why doesn't C# .NET SortedList actually have ElementAt?

.NET Documentation for 3.5 Collections.Generic.SortedList In the documentation, it plainly states that "ElementAt" is an extension method on SortedList members. Well, I've got one, declared thusly: private SortedList<int, ChainLink> linksByLevel = new SortedList<int, ChainLink>(); I try to get the last element: ChainLink lastLink = linksByLevel.ElementAt(linksByLevel.Count - 1); The compiler throws the massively helpful message: Error 1 'System.Collections.Generic.SortedList' does not contain a definition for 'ElementAt' and no extension method 'ElementAt' accepting a first argument of type '

Binary Search on Keys of SortedList<K, V>

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问题 I need to write some code for linear interpolation and I am trying to figure out the most efficient way to search the Keys of a SortedList<K, V> for the upper and lower keys that surround my target key. SortedList<int, double> xyTable = new SortedList<int, double>() { {1, 10}, {2, 20}, {3, 30}, {4,40} }; double targetX = 3.5; What is the most efficient way to search the list and determine that 3.5 is between 3 and 4? I have a method / cheat that works for integers (temporarily insert the

How to find an index at which a new item can be inserted into sorted list and keep it sorted?

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a = 132 b = [0, 10, 30, 60, 100, 150, 210, 280, 340, 480, 530] I want to know that a should be in the 6th position in ordered list b . What's the most pythonic way to do so? Use bisect . It's not the most beautiful API, but it's exactly what you need. You'll want to use bisect.bisect , which returns exactly what you want. bisect is a module in the Python Standard Library that is perfect for this task. The function bisect in the module bisect will give you the index of the insertion point for the value. Let me give a code example for bisect from bisect import bisect a = 132 b = [0, 10, 30, 60,

How do I increase the algorithm performance for longer array of numbers?

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问题 Thanks for looking. Count how many numbers are less than 4 in an ordered array of numbers. How do I increase the algorithm performance for longer array of numbers? Increase the calculation speed. Does binary search help? Outputs? public static int CountNumbers(int[] sortedArray, int lessThan) { int count = 0; for (int i = 0, len = sortedArray.Length; i < len; i++) if (sortedArray[i] < lessThan) count++; else return count; return count; } Assert.AreEqual(SortedSearch.CountNumbers(new int[] { 1

Android: SortedList with duplicates

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I have some problems understanding RecyclerView s SortedList . Lets say I have a very simple class only having a very simple class holding data: public class Pojo { public final int id; public final char aChar; public Pojo(int id, char aChar) { this.id = id; this.aChar = aChar; } @Override public String toString() { return "Pojo[" + "id=" + id + ",aChar=" + aChar + "]"; } } My understanding is that the sorted list won't contain any duplicates. But when I have a SortedList with callbacks like this: .... @Override public boolean areContentsTheSame(Pojo oldItem, Pojo newItem) { return oldItem