logo
down
shadow

Cost of SortedDictionary.Count


Cost of SortedDictionary.Count

By : aprophet13
Date : January 10 2021, 01:57 PM
this will help It simply returns a value from a field, so the cost should be neglectible.
code :


Share : facebook icon twitter icon
SortedDictionary<TKey, TValue>: check if contents equal to another SortedDictionary?

SortedDictionary<TKey, TValue>: check if contents equal to another SortedDictionary?


By : kahlersd
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further You will have to be prepared to loop through them all, but there are important short-cuts you can test for first.
First short-cut, is to check for object identity. While "A is A" isn't quite as profound as Ayn Rand seems to think, it is a handy way to make equality code faster. Identity always entails equality, and it is common in real code to end up comparing something to itself (esp in collection look-ups, loops and where an object is passed through several layers of code).
code :
public static bool EqualSortedDict<K, V>(SortedDictionary<K, V> x, SortedDictionary<K, V> y)
{
  if(ReferenceEquals(x, y))
    return true;
  if(ReferenceEquals(x, null) || ReferenceEquals(y, null))
    return false; //both being null already hit above.
  if(x.Count != y.Count)
    return false;
  if(!x.Comparer.Equals(y.Comparer))
    return false;//check if this is what you need. Probably is but might
                 //not be in some cases.
  foreach(KeyValuePair<K, V> kvp in x)
  {
    V cmpValue = default(V);
    if(!y.TryGetValue(kvp.Key, out cmpValue) || !kvp.Value.Equals(cmpValue))
      return false;
  }
  return true;
}
Count average cost and update cost of all products in column with conditions

Count average cost and update cost of all products in column with conditions


By : Imran
Date : March 29 2020, 07:55 AM
To fix this issue please help me with following:
code :
DECLARE @Average_cost

SELECT @Average_cost = AVG(UnitPrice)  FROM Products  
UPDATE Products
SET UnitPrice = (CASE WHEN UnitPrice > @Average_cost 
                      THEN UnitPrice - (UnitPrice * .1)
                      WHEN UnitPrice < @Average_cost 
                      THEN UnitPrice + (UnitPrice * .2)  
                      ELSE @Average_cost                   
                END) 
minimum cost path through a cost matrix with positive and negative cost

minimum cost path through a cost matrix with positive and negative cost


By : Inez Jester
Date : March 29 2020, 07:55 AM
hope this fix your issue Let's say that H[i, j] is the minimum health the player needs when starting from square (i, j). We are interested in H[1, 1], which is the minimum health needed from the starting square.
I assume that all values in the cost matrix M are integers. Therefore, the smallest positive health is 1.
code :
H[m, n] = max(1 - M[m, n], 1)
H[m, i] = max(H[m, i+1] - M[m, i], 1)
H[j, n] = max(H[j+1, n] - M[j, n], 1)
H[i, j] = min(max(H[i, j+1] - M[i, j], 1),
              max(H[i+1, j] - M[i, j], 1))
int[] H = new int[m, n];

H[m, n] = max(1 - M[m, n], 1);

// remember to loop backwards
for (int i = m-1; i >= 1; i--)
    H[m, i] = max(H[m, i+1] - M[m, i], 1);
for (int j = n-1; j >= 1; j--)
    H[j, n] = max(H[j+1, n] - M[j, n], 1);

// again, loop backwards
for (int i = m-1; i >= 1; i--)
    for (int j = n-1; j >= 1; j--)
        H[i, j] = min(max(H[i, j+1] - M[i, j], 1),
                      max(H[i+1, j] - M[i, j], 1));

return H[1, 1];
Postgres EXPLAIN ANALYZE cost estimate row count massively higher than actual row count. No Vacuuming?

Postgres EXPLAIN ANALYZE cost estimate row count massively higher than actual row count. No Vacuuming?


By : mattlezeay
Date : March 29 2020, 07:55 AM
wish helps you I have a Postgres 9.4.18 database running on Heroku in a Django project. I had noticed that queries were becoming increasingly slow so I ran an "EXPLAIN ANALYZE" on one query and noticed that for one node the row estimate was massively higher than the actual row count: , To find out if autovacuum is enabled as it should be, run
code :
SHOW autovacuum;
SELECT reloptions FROM pg_class WHERE relname = 'listings_listing';
ALTER TABLE listings_listing SET (
   autovacuum_vacuum_cost_limit = 1000,
   toast.autovacuum_vacuum_cost_limit = 1000
);
ALTER TABLE listings_listing SET (
   autovacuum_vacuum_cost_delay = 0,
   toast.autovacuum_vacuum_cost_delay = 0
);
SELECT n_live_tup, n_dead_tup, last_vacuum, last_autovacuum
FROM pg_stat_user_tables
WHERE relname = 'listings_listing';
How to compare values from one SortedDictionary to Add them to a new SortedDictionary?

How to compare values from one SortedDictionary to Add them to a new SortedDictionary?


By : user2679047
Date : March 29 2020, 07:55 AM
I wish did fix the issue. Here is an incomplete attempt using LINQ to obtain two sequences, one for enumerating forward (starting from the max item) and one for enumerating backward. After that point it is not easy to continue with LINQ, because the two sequences must be enumerated parallely in a complex way, so I went with a while loop.
code :
var mainsd = new SortedDictionary<double, int>()
{
    {500.10, 500}, {500.09, 1000}, {500.08, 2000}, {500.07, 3000},
    {500.06, 4500}, {500.05, 5500}, {500.04, 6000}, {500.03, 7000},
    {500.02, 8500}, {500.01, 9500}, {500.00, 10000}, {499.99, 9000},
    {499.98, 8000}, {499.97, 7500}, {499.96, 6500}, {499.95, 5000},
    {499.94, 4000}, {499.93, 3500}, {499.92, 2500}, {499.91, 1500},
    {499.90, 550},
};
var maxValue = mainsd.Max(e => e.Value);
var maxItemKey = mainsd.First(e => e.Value == maxValue).Key;
var forward = mainsd.SkipWhile(e => e.Key <= maxItemKey).ToArray();
var backward = mainsd.TakeWhile(e => e.Key < maxItemKey).Reverse().ToArray();
int i1 = 0;
int i2 = 0;
while (true)
{
    var sum1 = i1 < forward.Length - 1 ? forward[i1].Value + forward[i1 + 1].Value : 0;
    var sum2 = i2 < backward.Length - 1 ? backward[i2].Value + backward[i2 + 1].Value : 0;
    if (sum1 == 0 && sum2 == 0) break;
    if (sum1 >= sum2)
    {
        Console.WriteLine($"Forward:  {sum1}, Keys: {forward[i1].Key}, {forward[i1 + 1].Key}");
        i1 += 2;
    }
    else
    {
        Console.WriteLine($"Backward: {sum2}, Keys: {backward[i2 + 1].Key}, {backward[i2].Key}");
        i2 += 2;
    }
}
Forward:  18000, Keys: 500,01, 500,02
Backward: 17000, Keys: 499,98, 499,99
Backward: 14000, Keys: 499,96, 499,97
Forward:  13000, Keys: 500,03, 500,04
Forward:  10000, Keys: 500,05, 500,06
Backward: 9000, Keys: 499,94, 499,95
Backward: 6000, Keys: 499,92, 499,93
Forward:  5000, Keys: 500,07, 500,08
Backward: 2050, Keys: 499,9, 499,91
Forward:  1500, Keys: 500,09, 500,1
var valuesd = new SortedDictionary<double, int>();
valuesd.Add(forward[i1].Key, forward[i1].Value);
valuesd.Add(forward[i1 + 1].Key, forward[i1 + 1].Value);
valuesd.Add(backward[i2].Key, backward[i2].Value);
valuesd.Add(backward[i2 + 1].Key, backward[i2 + 1].Value);
if (valuesd.Values.Sum() >= mainsd.Values.Sum() * 50 / 100) break;
Related Posts Related Posts :
  • Looking for a .Net ORM
  • All possible combinations of n items selected randomly from a set of x items (algorithm)
  • Displaying process percentage on DOS screen
  • C# Importing Large Volume of Data from CSV to Database
  • c# control location precision
  • Printing to Zebra printer gives faint and blurry images
  • How to avoid stepping into dll code file?
  • Programmaticaly prevent Vista desktop search (WDS) from indexing pst files placed on mapped network drives
  • Is there anyway to reduce IsolatedStorage capacity in Silverlight?
  • C#: How to print a unicode string to console?
  • Frequency Table with Random Values
  • My Visual Studio 2008 web application keeps throwing a .Net error when I first run it, but refreshing fixes it
  • TCP Connection Creation and Closing Event Hooking
  • Find changed properties of a class
  • C#: Object with custom marshaller not containing data after PInvoke call
  • Version Control System with API. Need to get metrics
  • Performance comparison of Dictionaries
  • How to get process name and title of the top window on Windows / C#
  • How to save the ListView contents to a text file?
  • Why not .NET-style delegates rather than closures in Java?
  • Get CLSID by PIA interface Type
  • Visual Studio 2008 C# - Recover solution from application manifest possible?
  • Is a good practice to initialize private data members from within ctor by calling the associated properties instead of t
  • Inserting into a bitstream
  • How do you write byte[] array using log4.net
  • Clickonce + .NET client profile 4 framework + offline
  • Show form that showDialog from mainForm won't block it, but closing mainForm will close it
  • Developing a GPS car tracking system
  • dynamic log4net appender name?
  • Visual studio formatting issue
  • IndexOutOfRangeException when a stream is a multiple of the buffer size
  • How to deal with calculated values with Dependency Properties on a custom WPF control
  • counting from textbox,asp.net
  • Threading best practice when using SFTP in C#
  • how to load PDF file in website page using C#
  • Parent child class relationship design pattern
  • MessageQueue.BeginReceive() null ref error - c#
  • A C# collection, which behaves like C++ set or priority_queue?
  • Animating WPF buttons from inside a style
  • WPF Grid : GridSplitter event
  • Server 2008 Task Scheduler Mapped Drive Access C#
  • Cast problem with LINQ
  • Combo box Item source = ObservableCollection & I need a '-None-' dummy entry at the top
  • Which GUI control is suitable for this purpose?
  • Trying to access App.config file for mail settings but fails to work
  • Invoke PowerShell script from c# in runspace and get line number where error occured
  • How to show html contents with a RichTextBox?
  • FTP monitoring and downloading of new files
  • MEF + Plug-In not updating
  • Efficient handling of super wide, but not so tall, bitmap?
  • .NET 3.0 Unit Testing getting System.MethodAccessException calling .NET 2.0
  • Web Services vs Persistent Sockets
  • How do I dynamically reference incremented properties in C#?
  • Windows Installer (C#) error code 2869
  • Exception "The operation is not valid for the state of the transaction" using TransactionScope
  • Tools for listing database accesses from .NET code
  • Excel VSTO set selection
  • Creating a subscription based website in ASP.NET
  • Merging Resources Dictionaries
  • How to launch a .bat file in a C# windows Service project
  • shadow
    Privacy Policy - Terms - Contact Us © 35dp-dentalpractice.co.uk