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C# SPOJ time optimalization

I'm trying to get the job done MOHIBPIZ - PIZZA (https://www.spoj.com/problems/MOHIBPIZ/).
I'm already sitting on it the second day, I've tried everything I can and found on the internet. The last chance before giving up is to ask you guys
For recudces time I'm using InputOutput class created by davidsekar (https://github.com/davidsekar/C-sharp-Programming-IO/blob/master/ConsoleInOut/InputOutput.cs)
but still I have time "time limit exceeded". :(
I tried with two loops, but the method with the function seems more optimal to me. Thanks in advance for all the hints, suggestions and answers.
This is code (link on ideone: https://ideone.com/):
using System;
using System.IO;
public class Test
{
public static void Main()
{
InputOutput reader = new InputOutput();
StreamWriter _output = new StreamWriter(Console.OpenStandardOutput());
int T = reader.ReadInt();
for (int i = 0; i < T; i++)
{
_output.WriteLine(Recursion(reader.ReadInt()));
}
_output.Flush();
}
private static int Recursion(int x)
{
if(x <= 1)
{
return 2;
}
else
{
return Recursion(x - 1) + x;
}
}
#region Input Output Helper
public class InputOutput : System.IDisposable
{
private System.IO.Stream _readStream, _writeStream;
private int _readIdx, _bytesRead, _writeIdx, _inBuffSize, _outBuffSize;
private readonly byte[] _inBuff, _outBuff;
private readonly bool _bThrowErrorOnEof;
public void SetBuffSize(int n)
{
_inBuffSize = _outBuffSize = n;
}
public InputOutput(bool throwEndOfInputsError = false)
{
_readStream = System.Console.OpenStandardInput();
_writeStream = System.Console.OpenStandardOutput();
_readIdx = _bytesRead = _writeIdx = 0;
_inBuffSize = _outBuffSize = 1 << 22;
_inBuff = new byte[_inBuffSize];
_outBuff = new byte[_outBuffSize];
_bThrowErrorOnEof = throwEndOfInputsError;
}
public void SetFilePath(string strPath)
{
strPath = System.IO.Path.GetFullPath(strPath);
_readStream = System.IO.File.Open(strPath, System.IO.FileMode.Open);
}
public T ReadNumber<T>()
{
byte rb;
while ((rb = GetByte()) < '-')
;
var neg = false;
if (rb == '-')
{
neg = true;
rb = GetByte();
}
dynamic m = (T)Convert.ChangeType(rb - '0', typeof(T));
while (true)
{
rb = GetByte();
if (rb < '0')
break;
m = m * 10 + (rb - '0');
}
return neg ? -m : m;
}
public int ReadInt()
{
byte readByte;
while ((readByte = GetByte()) < '-')
;
var neg = false;
if (readByte == '-')
{
neg = true;
readByte = GetByte();
}
var m = readByte - '0';
while (true)
{
readByte = GetByte();
if (readByte < '0')
break;
m = m * 10 + (readByte - '0');
}
return neg ? -m : m;
}
public string ReadString()
{
return ReadString(' ');
}
public string ReadString(string delimiter)
{
return ReadString(delimiter[0]);
}
public string ReadString(char delimiter)
{
byte readByte;
while ((readByte = GetByte()) <= delimiter)
;
System.Text.StringBuilder sb = new System.Text.StringBuilder();
do
{
sb.Append((char)readByte);
} while ((readByte = GetByte()) > delimiter);
return sb.ToString();
}
[System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]
private byte GetByte()
{
if (_readIdx >= _bytesRead)
{
_readIdx = 0;
_bytesRead = _readStream.Read(_inBuff, 0, _inBuffSize);
if (_bytesRead >= 1)
return _inBuff[_readIdx++];
if (_bThrowErrorOnEof)
throw new System.Exception("End Of Input");
_inBuff[_bytesRead++] = 0;
}
return _inBuff[_readIdx++];
}
public void WriteToBuffer(string s)
{
foreach (var b in System.Text.Encoding.ASCII.GetBytes(s))
{
if (_writeIdx == _outBuffSize)
Flush();
_outBuff[_writeIdx++] = b;
}
}
public void WriteLineToBuffer(string s)
{
WriteToBuffer(s);
if (_writeIdx == _outBuffSize)
Flush();
_outBuff[_writeIdx++] = 10;
}
public void WriteToBuffer(int c)
{
byte[] temp = new byte[10];
int tempidx = 0;
if (c < 0)
{
if (_writeIdx == _outBuffSize)
Flush();
_outBuff[_writeIdx++] = (byte)'-';
c = -c;
}
do
{
temp[tempidx++] = (byte)((c % 10) + '0');
c /= 10;
} while (c > 0);
for (int i = tempidx - 1; i >= 0; i--)
{
if (_writeIdx == _outBuffSize)
Flush();
_outBuff[_writeIdx++] = temp[i];
}
}
public void WriteLineToBuffer(int c)
{
WriteToBuffer(c);
if (_writeIdx == _outBuffSize)
Flush();
_outBuff[_writeIdx++] = 10;
}
private void Flush()
{
_writeStream.Write(_outBuff, 0, _writeIdx);
_writeStream.Flush();
_writeIdx = 0;
}
public void Dispose()
{
Flush();
_writeStream.Close();
_readStream.Close();
}
}
#endregion Input Output Helper
}

As far as I can see, you have a well known Circle Division problem; see also A000124 sequence:
number of pieces after n cuts are (n * n + n + 2) / 2
That's why we can put O(1) time and space complexity
Code:
private static int Solution(int n) => (int)(((long)n * n + n + 2) / 2);
Here I've put (long) n in case n * n exceeds int.MaxValue, when (n * n + n + 2) / 2 doesn't.
Edit: I've implemented int Solution(int n) method which is based on current code int Recursion(int x) signature; but if there're tests for large n we are going to have integer overflow.
In this case
private static long Solution(long n) =>
1 + (n % 2 == 0 ? n / 2 * (n + 1) : (n + 1) / 2 * n);
In case of arbitrary n we have to use BigInteger:
using System.Numerics;
...
private static BigInteger Solution(BigInteger n) =>
1 + (n * n + n) / 2;

Can't figure out why my function is not being called

Not sure how stackoverflow questions work, but I am trying to piggy-back off my earlier issue.
I have got rid of all the errors and dig is not null anymore because I actually needed it to have a value and I realized that from people's help earlier but now my function is not being called.
What am I missing??
"Dig" is defined early in my code (public string dig = default;)
private void button1_Click(object sender, EventArgs e)
{
using (StreamWriter objWriter = new StreamWriter("C:\\temp\\Test.txt"))
{
int numpins = int.Parse(textBox1.Text);
string basepin = textBox2.Text;
int pinlength = basepin.Length;
string formatspecifier = "{0:d" + pinlength.ToString() + "}";
long pinnumber = long.Parse(basepin);
for (int d = 0; d < numpins; d++)
{
dig = basepin;
if (dig == null)
{
throw new Exception("null value not allowed");
}
else
{
GetCheckDigit(dig);
}
basepin = string.Format(formatspecifier, pinnumber);
objWriter.WriteLine(basepin);
pinnumber++;
}
objWriter.Close();
}
}
This is my function
private static string GetCheckDigit(string dig)
{
var sum = 0;
var result = true;
var digits = dig.ToCharArray();
for (int i = digits.Length - 1; i >= 0; i--)
{
var num = digits[i] - 48;
if (result)
{
num *= 2;
if (num > 9)
num -= 9;
}
sum += num;
result = !result;
}
if ((sum % 10) == 0)
{
return "0";
}
return (10 - (sum % 10)).ToString();
}

Unless numpins is lower than 0 or basepin is null, GetCheckDigit(dig) is being called.
In case you meant it doesn't output anything to the screen it's because
GetCheckDigit(dig) doesn't output anything to screen, just returns the string.

How to increment mixed Alphanumeric in C#?

I have requirements in a project to generate sequential rows and columns which are alphanumeric values.
The end user will pass the start value of row and column he would like to start from, and how many rows and columns he wants to generate.
For letters the max value is Z
For numbers the max values is 9
If the end user passed these parameters:
StartRow = 0A
StartColumn = A9Z
rowsCount = 2
columnsCount = 5
I would like to get this result:

You might want to reconsider your approach. Rather than maintaining an alphanumeric value and trying to increment it, maintain the value as a class containing Row and Column values, and then use ToString to convert it to the alphanumeric representation. Like this:
class RowCol
{
private int _row;
private int _col;
public int Row
{
get { return _row; }
set
{
// Row is of the form <digit><letter
// giving you 260 possible values.
if (value < 0 || value > 259)
throw new ArgumentOutOfRangeException();
_row = value;
}
}
public int Col
{
get { return _col; }
set
{
// Col is <letter><digit><letter>,
// giving you 6,760 possible values
if (value < 0 || value > 6759)
throw new ArgumentOutOfRangeException();
_col = value;
}
}
public string RowString
{
get
{
// convert Row value to string
int r, c;
r = Math.DivMod(_row, 26, out c);
r += '0';
c += 'A';
return string.Concat((char)r, (char)c);
}
set
{
// convert string to number.
// String is of the form <letter><digit>
if (string.IsNullOrEmpty(value) || value.Length != 2
|| !Char.IsDigit(value[0] || !Char.IsUpper(value[1]))
throw new ArgumentException();
_row = 26*(value[0]-'0') + (value[1]-'A');
}
}
public string ColString
{
get
{
int left, middle, right remainder;
left = Math.DivRem(_col, 260, out remainder);
middle = Math.DivRem(remainder, 26, out right);
left += 'A';
middle += '0';
right += 'A';
return string.Concat((char)left, (char)middle, (char)right);
}
set
{
// Do standard checking here to make sure it's in the right form.
if (string.IsNullOrEmpty(value) || value.Length != 3
|| !Char.IsUpper(value[0] || !Char.IsDigit(value[1]) || !Char.IsUpper(value[2]))
throw new ArgumentException();
_col = 260*(value[0] - 'A');
_col += 26*(value[1] - '0');
_col += value[2] - 'A';
}
}
public override string ToString()
{
return RowString + '-' + ColString;
}
public RowCol(int row, int col)
{
Row = _row;
Col = _col;
}
public RowCol(string row, string col)
{
RowString = row;
RowString = col;
}
}
(Code not yet tested, but that's the general idea.)
That's a bit more code than you have, it hides the complexity in the RowCol class rather than forcing you to deal with it in your main program logic. The point here is that you just want to increment the row or column; you don't want to have to think about how that's done. It makes your main program logic easier to understand. For example:
string startRow = "0A";
string startCol = "B0A";
RowCol rc = new RowCol("0A", "B0A");
for (int r = 0; r < rowsCount; r++)
{
rc.ColString = "B0A";
for (int c = 0; c < columnsCount; c++)
{
Console.WriteLine(rc);
rc.Row = rc.Row + 1;
}
rc.Col = rc.Col + 1;
}
By casting this as a simple conversion problem and encapsulating it in a class, I've made the code more robust and flexible, and easier to test, understand, and use.

I have come up with very simple solution to implement that and I would like to share this Console application :
class Program
{
static void Main(string[] args)
{
var row = "0A";
var column = "A9Z";
var rowsCount = 2;
var columnsCount = 5;
var rowCharArray =row.ToArray().Reverse().ToArray();
var columnCharArray = column.ToArray().Reverse().ToArray();
for (int i = 0; i < rowsCount; i++)
{
for (int j = 0; j < columnsCount; j++)
{
columnCharArray = incrementChar(columnCharArray);
var currentColumn = string.Join("", columnCharArray.Reverse().ToArray());
var currentRow= string.Join("", rowCharArray.Reverse().ToArray());
Console.WriteLine(currentRow + "-" + currentColumn);
}
columnCharArray = column.ToArray().Reverse().ToArray();
rowCharArray= incrementChar(rowCharArray);
Console.WriteLine("-------------------------------");
}
Console.ReadLine();
}
static char[] incrementChar(char[] charArray,int currentIndex=0)
{
char temp = charArray[currentIndex];
if (charArray.Length -1 == currentIndex && (temp == '9' || temp == 'Z'))
throw new Exception();
temp++;
if(Regex.IsMatch(temp.ToString(),"[A-Z]"))
{
charArray[currentIndex] = temp;
}
else
{
if (Regex.IsMatch(temp.ToString(), "[0-9]"))
{
charArray[currentIndex] = temp;
}
else
{
currentIndex++;
incrementChar(charArray, currentIndex);
}
}
if (currentIndex != 0)
charArray = resetChar(charArray, currentIndex);
return charArray;
}
static char[] resetChar(char[] charArray,int currentIndex)
{
for (int i = 0; i < currentIndex; i++)
{
if (charArray[i] == 'Z')
charArray[i] = 'A';
else if (charArray[i] == '9')
charArray[i] = '0';
}
return charArray;
}
}

How to display the result of a char variable in a Windows Form Based application using C#

public void caesarcipher()
{
char c, a;
string PT = textBox1.Text;
PT = PT.ToLower();
for (int i = 0; i < PT.Length; i++)
{
c = Convert.ToChar(PT.Substring(i, 1));
if ((int)c + 3 > 122) a = (char)(c + 3 - 26);
else a = (char)(c + 3);
label2.Text = a; //error here as label can not display char
}
}
private void button1_Click(object sender, EventArgs e)
{
caesarcipher();
}
That is my partial code, what I want is that to display all the elements stored in char a in a label and converting the char a to string displays only the last element which does not help.
I hope I am clear enough.

This did the trick thanks to #BradleyUffner and #ChrisDunaway
public void caesarcipher()
{
char c, a;
string PT = textBox1.Text;
PT = PT.ToLower();
label2.Text = " "; //added this line
for (int i = 0; i < PT.Length; i++)
{
c = PT[i]; //changed
//c = Convert.ToChar(PT.Substring(i, 1));
if ((int)c + 3 > 122) a = (char)(c + 3 - 26);
else a = (char)(c + 3);
label2.Text += a.ToString(); //changes here solved the error
}
}

You just need to add each character to the label2.Text property instead of reassigning the property. You can also get rid of some of the explicit casting; char will get cast to an int implicitly when added to an `int:
public void CaesarCipher()
{
label2.Text = "";
foreach (var character in textBox1.Text.ToLower())
{
var intVal = character + 3;
label2.Text += (char)(intVal > 122 ? intVal - 26 : intVal);
}
}

Unless I'm missing something, a will ever only hold a single char since you defined it as char a and are setting it equal to a char.
For this, you would need to change the definitions to char[] a = new char[PT.Length]
Instead calling a =, you would then have to use the index to set the char at the location to what you want. Replacing a = with a[i] = would suffice.
To display the char array, label2.Text = new string(a) will do the trick.
public void caesarcipher()
{
string PT = textBox1.Text;
PT = PT.ToLower();
char c;
char[] a = new char[PT.Length];
for (int i = 0; i < PT.Length; i++)
{
c = Convert.ToChar(PT.Substring(i, 1));
if ((int)c + 3 > 122) a[i] = (char)(c + 3 - 26);
else a[i] = (char)(c + 3);
}
label2.Text = new string(a);
}
private void button1_Click(object sender, EventArgs e)
{
caesarcipher();
}

Count occurences in byte list/array using another byte list/array

I am trying to get a count of all the times a byte sequences occurs in another byte sequences. It cannot however re-use a bytes if it already counted them. For example given the string
k.k.k.k.k.k. let's assume the byte sequence was k.k it would then find only 3 occurrences rather than 5 because they would be broke down like: [k.k].[k.k].[k.k]. and not like [k.[k].[k].[k].[k].k] where they over lap and essentially just shift 2 to the right.
Ideally the idea is to get an idea how a compression dictionary or run time encoding might look. so the goal would be to get
k.k.k.k.k.k. down to just 2 parts, as (k.k.k.) is the biggest and best symbol you can have.
Here is source so far:
using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.IO;
static class Compression
{
static int Main(string[] args)
{
List<byte> bytes = File.ReadAllBytes("ok.txt").ToList();
List<List<int>> list = new List<List<int>>();
// Starting Numbers of bytes - This can be changed manually.
int StartingNumBytes = bytes.Count;
for (int i = StartingNumBytes; i > 0; i--)
{
Console.WriteLine("i: " + i);
for (int ii = 0; ii < bytes.Count - i; ii++)
{
Console.WriteLine("ii: " + i);
// New pattern comes with refresh data.
List<byte> pattern = new List<byte>();
for (int iii = 0; iii < i; iii++)
{
pattern.Add(bytes[ii + iii]);
}
DisplayBinary(bytes, "red");
DisplayBinary(pattern, "green");
int matches = 0;
// foreach (var position in bytes.ToArray().Locate(pattern.ToArray()))
for (int position = 0; position < bytes.Count; position++) {
if (pattern.Count > (bytes.Count - position))
{
continue;
}
for (int iiii = 0; iiii < pattern.Count; iiii++)
{
if (bytes[position + iiii] != pattern[iiii])
{
//Have to use goto because C# doesn't support continue <level>
goto outer;
}
}
// If it made it this far, it has found a match.
matches++;
Console.WriteLine("Matches: " + matches + " Orig Count: " + bytes.Count + " POS: " + position);
if (matches > 1)
{
int numBytesToRemove = pattern.Count;
for (int ra = 0; ra < numBytesToRemove; ra++)
{
// Remove it at the position it was found at, once it
// deletes the first one, the list will shift left and you'll need to be here again.
bytes.RemoveAt(position);
}
DisplayBinary(bytes, "red");
Console.WriteLine(pattern.Count + " Bytes removed.");
// Since you deleted some bytes, set the position less because you will need to redo the pos.
position = position - 1;
}
outer:
continue;
}
List<int> sublist = new List<int>();
sublist.Add(matches);
sublist.Add(pattern.Count);
// Some sort of calculation to determine how good the symbol was
sublist.Add(bytes.Count-((matches * pattern.Count)-matches));
list.Add(sublist);
}
}
Display(list);
Console.Read();
return 0;
}
static void DisplayBinary(List<byte> bytes, string color="white")
{
switch(color){
case "green":
Console.ForegroundColor = ConsoleColor.Green;
break;
case "red":
Console.ForegroundColor = ConsoleColor.Red;
break;
default:
break;
}
for (int i=0; i<bytes.Count; i++)
{
if (i % 8 ==0)
Console.WriteLine();
Console.Write(GetIntBinaryString(bytes[i]) + " ");
}
Console.WriteLine();
Console.ResetColor();
}
static string GetIntBinaryString(int n)
{
char[] b = new char[8];
int pos = 7;
int i = 0;
while (i < 8)
{
if ((n & (1 << i)) != 0)
{
b[pos] = '1';
}
else
{
b[pos] = '0';
}
pos--;
i++;
}
//return new string(b).TrimStart('0');
return new string(b);
}
static void Display(List<List<int>> list)
{
//
// Display everything in the List.
//
Console.WriteLine("Elements:");
foreach (var sublist in list)
{
foreach (var value in sublist)
{
Console.Write("{0,4}", value);
}
Console.WriteLine();
}
//
// Display total count.
//
int count = 0;
foreach (var sublist in list)
{
count += sublist.Count;
}
Console.WriteLine("Count:");
Console.WriteLine(count);
}
static public int SearchBytePattern(byte[] pattern, byte[] bytes)
{
int matches = 0;
// precomputing this shaves some seconds from the loop execution
int maxloop = bytes.Length - pattern.Length;
for (int i = 0; i < maxloop; i++)
{
if (pattern[0] == bytes[i])
{
bool ismatch = true;
for (int j = 1; j < pattern.Length; j++)
{
if (bytes[i + j] != pattern[j])
{
ismatch = false;
break;
}
}
if (ismatch)
{
matches++;
i += pattern.Length - 1;
}
}
}
return matches;
}
}
Refer to the post to get the non binary of the file should be, here is the binary data:
011010110010111001101011001011100110101100101110011010110010111001101011001011100110101100101110 I am hope to have it smaller than how it started.

private static int CountOccurences(byte[] target, byte[] pattern)
{
var targetString = BitConverter.ToString(target);
var patternString = BitConverter.ToString(pattern);
return new Regex(patternString).Matches(targetString).Count;
}

With this solution you'd have access to the individual indexes that matched (while enumerating) or you could call Count() on the result to see how many matches there were:
public static IEnumerable<int> Find<T>(T[] pattern, T[] sequence, bool overlap)
{
int i = 0;
while (i < sequence.Length - pattern.Length + 1)
{
if (pattern.SequenceEqual(sequence.Skip(i).Take(pattern.Length)))
{
yield return i;
i += overlap ? 1 : pattern.Length;
}
else
{
i++;
}
}
}
Call it with overlap: false to solve your problem or overlap: true to see the overlapped matches (if you're interested.)
I have a couple of other methods with slightly different API (along with better performance) here, including one that work directly on streams of bytes.

quick and dirty with no regex. although i'm not sure if it answers the intent of the question, it should be relatively fast. i think i am going to run some timing tests against regex to see for sure the relative speeds:
private int CountOccurrences(string TestString, string TestPattern)
{
int PatternCount = 0;
int SearchIndex = 0;
if (TestPattern.Length == 0)
throw new ApplicationException("CountOccurrences: Unable to process because TestPattern has zero length.");
if (TestString.Length == 0)
return 0;
do
{
SearchIndex = TestString.IndexOf(TestPattern, SearchIndex);
if (SearchIndex >= 0)
{
++PatternCount;
SearchIndex += TestPattern.Length;
}
}
while ((SearchIndex >= 0) && (SearchIndex < TestString.Length));
return PatternCount;
}
private void btnTest_Click(object sender, EventArgs e)
{
string TestString1 = "k.k.k.k.k.k.k.k.k.k.k.k";
string TestPattern1 = "k.k";
System.Console.WriteLine(CountOccurrences(TestString1, TestPattern1).ToString()); // outputs 6
System.Console.WriteLine(CountOccurrences(TestString1 + ".k", TestPattern1).ToString()); // still 6
System.Console.WriteLine(CountOccurrences(TestString1, TestPattern1 + ".").ToString()); // only 5
}