cumulative-sum

问题 What is the best way to maintain a "cumulative sum" of a particular data column in SQLite? I have found several examples online, but I am not 100% certain how I might integrate these approaches into my ContentProvider . In previous applications, I have tried to maintain cumulative data myself, updating the data each time I insert new data into the table. For example, in the sample code below, every time I would add a new record with a value score , I would then manually update the value of

问题 First, define a string of "balanced" parentheses as a string such that for every '(' there is one unique, matching ')' somewhere after that '('. For example, the following strings are all "balanced": () ()() (())() while these are not: )( ())( Given a string of parentheses (length <= 1,000,000) and a list of range queries, find the maximum length of balanced parentheses within each of the ranges for each of the <= 100,000 queries (using 0-indexing for the ranges) Ex: ()))()(()) Range: [0,3] -

问题 I'm reading a sparse table from a file which looks like: 1 0 7 0 0 1 0 0 0 5 0 0 0 0 2 0 0 0 0 1 0 0 0 1 1 0 0 1 0 0 0 3 0 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 2 0 0 0 0 1 0 0 0 1 0 1 0 0 1 1 0 0 1 0 3 0 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 2 0 0 0 0 1 0 0 0 1 0 1 0 0 1 1 2 1 0 1 0 1 Note row lengths are different. Each row represents a single simulation. The value in the i-th column in each row says how many times value i-1 was observed in this simulation. For example, in the first simulation (first row),

问题 I have a table with following data: computed column : current | id | Date (dd/mm/yyyy) | Factor | Actual | Current | |----|-------------------|--------|--------|----------| | 1 | 04/01/2017 | 0.5 | 100 | 100 | | 2 | 04/02/2017 | 0.5 | 120 | 100 | | 3 | 04/03/2017 | 0.5 | 120 | 110 | | 4 | 04/04/2017 | 0.5 | 115 | 115 | | 5 | 04/05/2017 | 0.5 | 125 | 115 | | 6 | 04/06/2017 | 0.5 | 100 | 120 | | 7 | 04/07/2017 | 0.5 | 100 | 110 | Current row = current of previous row + factor * (actual of

问题 I have a large list, an excerpt of which looks like: power = [ ['1234-43211', [5, 6, -4, 11, 22]], ['1234-783411', [43, -5, 0, 0, -1]], ['1234-537611', [3, 0, -5, -6, 0]], ['1567-345411', [4, 6, 8, 3, 3]], ['1567-998711', [1, 2, 1, -4, 5]] ] The first number in the string is the important one, and the one in which I hope to separate my additions. i.e. I only want to add cumulatively the values within each station (and return each singular cumulative addition), never add the values from two

问题 I want to calculate a cumulative sum of the values in column 2 of dat.txt below for each string of ones in column 1. The desired output is shown as dat2.txt : dat.txt dat2.txt 1 20 1 20 20 % 20 + 0 1 22 1 22 42 % 20 + 22 1 20 1 20 62 % 42 + 20 0 11 0 11 11 0 12 0 12 12 1 99 1 99 99 % 99 + 0 1 20 1 20 119 % 20 + 99 1 50 1 50 169 % 50 + 119 Here's my initial attempt: fid=fopen('dat.txt'); A =textscan(fid,'%f%f'); in =cell2mat(A); fclose(fid); i = find(in(2:end,1) == 1 & in(1:end-1,1)==1)+1; out

问题 The second section of this answer uses variables to create a cumulative sum of another column. I'm doing the same thing, except that I am using a GROUP BY statement, and summing COUNT(*) instead of a column. Here is my code to create a minimal table and insert values: CREATE TABLE `test_group_cumulative` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT, `group_id` int(11) unsigned NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `test_group_cumulative` (`id`,

问题 I need to create a counter variable depending on three other variables. This is an extension question of this one.extension question Consider the situations of multiple consumers place order in Amazon. I want to count the successful order times by each user. If you have placed order successfully, the counter variable self plus one;if it is a failed order, the counter remains the same. Obviously, the counter variable will be depend on the time,order status and user. Please consider the

问题 I tried asking this question before but was it was poorly stated. This is a new attempt cause I haven't solved it yet. I have a dataset with winners, losers, date, winner_points and loser_points. For each row, I want two new columns, one for the winner and one for the loser that shows how many points they have scored so far (as both winners and losers). Example data: winner <- c(1,2,3,1,2,3,1,2,3) loser <- c(3,1,1,2,1,1,3,1,2) date <- c("2017-10-01","2017-10-02","2017-10-03","2017-10-04",

问题 As per Wikipedia: A summed area table is a data structure and algorithm for quickly and efficiently generating the sum of values in a rectangular subset of a grid. For a 2D space a summed area table can be generated by iterating x,y over the desired range, I(x,y) = i(x,y) + I(x-1,y) + I(x,y-1) - I(x-1,y-1) And the query function for a rectangle corners A(top-left) , B(top-right) , C(bottom-right) , D can be given by:- I(C) + I(A) - I(B) - I(D) I want to convert the above to 3D. Also please