multiset

问题 I have been working on a query to generate xml from the oracle database database where "column" is a type CREATE OR REPLACE TYPE "column" AS OBJECT ("coulmnname" VARCHAR2 (30), "datatype" VARCHAR2 (30)) and col_list_t is of type CREATE OR REPLACE TYPE col_list_t AS TABLE OF "column" and SELECT CAST ( MULTISET ( SELECT "column" (B.COLUMN_NAME, B.DATA_TYPE) FROM all_tab_columns b, all_tables c ,all_tables a WHERE b.TABLE_NAME = a.TABLE_NAME AND b.table_name = c.TABLE_NAME AND B.OWNER = C.OWNER

问题 I was trying the Facebook Hacker Cup 2013 Qualification Problems in Scala, and for the 3rd problem I felt the need of an ordered Multiset but could not find one in scala's (2.10) collections. Is this data structure missing in scala's collections. Is it going to be implemented in a future version? Is the Multiset not really necessary if you have already a set implemented? 回答1: A multiset is a rather peculiar and uncommon data structure. It is not, for instance, part of Java's standard library

问题 I try to replace std::multiset with std::priority_queue. But I was dissapointed with the speed results. Running time of the algorithm increase by 50%... Here are the corresponding commands: top() = begin(); pop() = erase(knn.begin()); push() = insert(); I am surprised with the speed of priority_queue implementation, I expected different results (better for PQ)... Conceptually, the multiset is being used as a priority queue. Why are the priority queue and the multiset have such different

问题 I'm looking for a .Net implementation of a multiset. Can anyone recommend a good one? (A multiset, or bag, is a set that can have duplicate values, and on which you can do set operations: intersection, difference, etc. A shopping cart for instance could be thought of as a multiset because you can have multiple occurrences of the same product.) 回答1: I do not know about one, however you could use a Dictionary for that, in which the value is the quantity of the item. And when the item is added

问题 I am porting some C++ code to Python and one of the data structures is a multiset, but I am not sure how to model this in Python. Let ms be the C++ multiset<int> How ms is used (posting some examples) multiset<int>::iterator it = ms.find(x) ms.erase(it) ms.insert(x) ms.end() ms.lower_bound(x) ms.clear() 回答1: There isn't. See Python's standard library - is there a module for balanced binary tree? for a general discussion of the equivalents of C++ tree containers ( map , set , multimap ,

问题 I have two strings and I would like to have the intersection on them including duplicate items: str_a = "aabbcc" str_b = "aabd" list(set(str_a) & set(str_b)) >> "ab" I would like to have it return: >> "aab" Any ideas? 回答1: Multisets are implemented in python 2.7 or later as (mutable) Counter objects. You can perform many of the same operations as you can for sets, such as union, intersection, difference (though counts can become negative), etc.: from collections import Counter as mset

问题 In this thread, I am trying to include all the commonly asked questions and their answers here. I hope this will be useful for someone. General question : How to generate sequences of r objects from n objects? combination vs permutation. with replacement vs without replacement. distinct items vs non-distinct items (multisets). There are in total 2^3=8 questions of this type. [Update] Josh O'Brien suggests that the 8 questions are related to twelvefold way. Indeed, the "distinct" questions are

问题 In this thread, I am trying to include all the commonly asked questions and their answers here. I hope this will be useful for someone. General question : How to generate sequences of r objects from n objects? combination vs permutation. with replacement vs without replacement. distinct items vs non-distinct items (multisets). There are in total 2^3=8 questions of this type. [Update] Josh O'Brien suggests that the 8 questions are related to twelvefold way. Indeed, the "distinct" questions are

问题 While I solve an algorithm question, My solution couldn't get passed because of time issue. But I realized that the only difference between passed one and mine was bag.lower_bound(jewerly[i].first) != bag.end() //passed lower_bound(bag.begin(), bag.end(), jewerly[i].first) != bag.end() //failed I've already checked it with clock() and It was obviously slower than the other one. what makes the difference between the two codes? #include <cstdio> #include <set> #include <algorithm> using

问题 I need a bag/multiset-like data type in Python. I understand collections.Counter is often used for this purpose. But the comparison operators don't seem to work: In [1]: from collections import Counter In [2]: bag1 = Counter(a=1, b=2, c=3) In [3]: bag2 = Counter(a=2, b=2) In [4]: bag1 > bag2 Out[4]: True This seems like a bug to me. I expected the less-than and greater-than operators to perform set-like subset and superset comparisons. But if that were the case then bag1 > bag2 would be false