multiset

问题 I am trying to find an efficient algorithm to find permutation of a multiset, given an index. Ex: given {1, 3, 3} . All permutations in an ascending lexicographic order are {133, 313, 331} . These elements are indexed as {0, 1, 2} . Given index=2 , the result is 331. I found an algorithm to find permutation of a set given a lexicographic index. His algorithm is efficient: O(n^2). However, the algorithm is tested on a proper set (e.g. {1, 2, 3} ), and not correct on my test. I describe his

问题 How should I iterate through a Nested Map with such declaration? Map<String, Multiset<String>> Please suggest if there are other hashmap/list that are more effective way of doing this hash population task? import com.google.common.collect.Multiset; import com.google.common.collect.TreeMultiset; String[] foobarness = {"foo" , "bar", "ness", "foo", "bar", "foo", "ness", "bar", "foo", "ness", "foo", "bar", "foo", "ness", "bar", "ness", "foo", "bar", "foo", "ness"}; String[] types = {"type::1",

问题 I have used MULTISET UNION in order to load a collection into another collection of the same type however I am now working with Records and want to add a Record into a Collection of the same Type. For whatever reason I just can't figure out the appropriate syntax or simply the proper way to do this as MULTISET UNION appears to not play nice with Records in the way I'm used to working with Collections. I've added a summary of how this code works at the end (supposed to work anyway). Screenshot

问题 I am using a for loop to pass different values to a cursor, bulk collect the data and append it to the same nested table using MULTISET UNION operator. However, to avoid duplicate data, i tried to use MULTISET UNION DISTINCT and it throws the error PLS-00306: wrong number or types of arguments in call to 'MULTISET_UNION_DISTINCT' The codes works well without DISTINCT. Please let me know if i'm missing anything here. I'm using Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit

问题 I know that JavaScript now has sets, but I wonder if there is something to realize the function of multiSet , or if there is some framework that has the functions of multiset which I really need a lot. Or I have to code it by myself to do the research of Red-Black Tree ? 回答1: There are no built-in multiset structure, but there are some libraries that have such: mnemonist → MultiSet TSTL → TreeMultiSet Feel free to add your favorite library in this question. 来源： https://stackoverflow.com

问题 I have a std::multiset, which stores std::pair. I want the first attribute to have no constraint on uniqueness, but I want the second one to be unique. So, I decided to pass my own function to multiset, in order to achieve this (if not please let me know). Based on this answer, I wrote a similar function but it fails, and I have no idea why (no idea of λ - and I am Greek :) ). auto f = [](std::pair<float, int>& a, std::pair<float, int>& b) { return (a.first < b.first && a.second != b.second);

问题 at first I'm new here and English isn't my native language so apologize for any grammatical failures but I find this community really nice so I will try to ask my question as precise as I can. I want to add my own class object into a stl container multiset and want to sort it with my own overloaded less operator defined in my class. I really tried out several solutions but nothing really worked so I hope someone can give me some useful hints to solve it. Here is my general idea of my class

问题 Say you have a List of 32-bit Integers and the same collection of 32-bit Integers in a Multiset (a set that allows duplicate members) Since Sets don't preserve order but List do, does this mean we can encode a Multiset in less bits than the List? If so how would you encode the Multiset? If this is true what other examples are there where not needing to preserve order saves bits? Note, I just used 32-bit Integers as an example. Does the data type matter in the encoding? Does the data type need

问题 Assuming we got 2 lists, always with the same length and always containing strings. list1 = ['sot', 'sot', 'ts', 'gg', 'gg', 'gg'] list2 = ['gg', 'gg', 'gg', 'gg', 'gg', 'sot'] we need to find: How many items of the list2 should change, in order for it to be equals with list1 . So on the previous example it should return 2 For this example: list1 = ['sot', 'sot', 'ts', 'gg', 'gg', 'gg'] list2 = ['gg', 'gg', 'gg', 'gg', 'sot', 'sot'] it should return 1 and finally for this example: list1 = [

问题 All I need is to know if something exists and how many times it exist. I will iterate over the existent things and query how much of that exists. My implementation so far uses multiset , I do as follow: std::multiset<thing> a; auto previous = a.end(); for( auto each = a.begin(); each != a.end(); ++each ) { if( previous == a.end() || *previous != *each ) { a.count(*each); } previous = each; } Clarifications I have a vector of thing s. But they repeat the value sometimes, I want to iterate over