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Convert oct to dex integer

Incorrectly converts a number
In the program you need to convert from octal number system to decimal
"a" is a integer class field that uses the GetDex() method
Construct - this.a = a;
public int GetDex()
{
int res = 0;
int exp = 1;
for (int i = Convert.ToString(a).Length - 1; i >= 0; i--)
{
res += exp * Convert.ToInt32(Convert.ToString(a)[i]);
exp *= 8;
}
return res;
}

The problem is in the
Convert.ToInt32(Convert.ToString(a)[i])
fragment. You actually add ascii codes, not digits. To get digit integer 5 from character '5' just subtract '0':
(Convert.ToString(a)[i] - '0')
Your code corrected:
public int GetDex()
{
int res = 0;
int exp = 1;
for (int i = Convert.ToString(a).Length - 1; i >= 0; i--)
{
//DONE: you should add digits, not ascii codes: - '0'
res += exp * (Convert.ToString(a)[i] - '0');
exp *= 8;
}
return res;
}
You can put it compact with a help of Linq:
public int GetDex() => a
.ToString()
.Aggregate(0, (s, i) => s * 8 + i - '0');

I wrote a program to get the count of matching adjacent alphabets in a string

For the same 1 of the test cases have passed while all the other had failed. The failed ones test cases were of very long strings. but could not understand where did I go wrong.
The number of test cases and string is been read in the main function, and string gets passed to this function.
public static int getMaxScore(string jewels)
{
string temp=jewels;
int count=0;
for(int i=0;i<temp.Length-1;i++)
{
for(int j=i;j<temp.Length-1;j++)
{
if(jewels[i]==jewels[j+1])
{
temp=jewels.Remove(i,2);
count++;
}
else
{
continue;
}
}
}
return count;
}
for the passed 1, there were 2 test cases. In that, one being jewels="abcddcbd" and the other being "abcd". Expected Output was 3 for the first string and 0 for the second. however, i got the expected output for this test case. but failed all other ones(those are very long strings)
jewels="edmamjboxwzfjsgnmycuutvkhzerdiabcvzlnoazreuavyemxqwgyzdvrzyohamwamziqvdduequyyspfipvigooyqmwllvp"
Can somebody help me in knowing what is wrong in my code or how can I obtain the result I want?
Thanks in Advance!!!

Sounds a Jewel Quest puzzle. Checking a string for adjacent equal characters, remove them and increase the counter by 1. Removing the two characters from the string could produce a new one with adjacent equal characters so it must be checked again from the beginning to remove them, increase the counter, and do it all over again until no more.
public static int getMaxScore(string jewels)
{
var count = 0;
var max = jewels.Length;
var i = 0;
var chars = jewels.ToList();
var adj = 2; //<- Change to increase the number of adjacent chars.
while (i < max)
{
if (chars.Count >= adj && i <= chars.Count - adj &&
chars.Skip(i).Take(adj).Distinct().Count() == 1)
{
count++;
chars.RemoveRange(i, adj);
max = chars.Count;
i = 0;
}
else
i++;
}
return count;
}
Testing:
void TheCaller()
{
Console.WriteLine(getMaxScore("abcddcbd"));
Console.WriteLine(getMaxScore("abcd"));
Console.WriteLine(getMaxScore("edmamjboxwzfjsgnmycuutvkhzerdiabcvzlnoazreuavyemxqwgyzdvrzyohamwamziqvdduequyyspfipvigooyqmwllvp"));
}
Writes 3, 0, and 5 respectively.

public static int CountThings(string s)
{
if(s.Length < 2) { return 0; }
int n = 0;
for (int i = 0; i < s.Length - 1; i++)
{
if (s[i] == s[i + 1])
{
int start = i;
int end = i + 1;
while (s[start] == s[end] && start >= 0 && end <= s.Length - 1)
{
n++;
start--;
end++;
}
}
}
return n;
}

For grits and shins, here's a compact recursive version:
static void Main(string[] args)
{
string jewels = "edmamjboxwzfjsgnmycuutvkhzerdiabcvzlnoazreuavyemxqwgyzdvrzyohamwamziqvdduequyyspfipvigooyqmwllvp";
int score = getMaxScore(new StringBuilder(jewels));
Console.WriteLine($"jewels = {jewels}");
Console.WriteLine($"score = {score}");
Console.Write("Press Enter to Quit.");
Console.ReadLine();
}
static int getMaxScore(StringBuilder jewels)
{
for(int i=0; i<(jewels.Length-1); i++)
if (jewels[i]==jewels[i+1])
return 1 + getMaxScore(jewels.Remove(i, 2));
return 0;
}

How to get integers to an array (from integer i to integer j). c#

I want to store integers(in an array or anything) that in range of int "i" and int "j".
eg:-Think, "int i = 1" and "int j = 10".I want to store integers from 1 and 10.
So that (1,2,3,4,5,6,7,8,9,10)
Because I want to answer to HackerRank "Beautiful Days at the Movies".
link below.
https://www.hackerrank.com/challenges/beautiful-days-at-the-movies/problem?isFullScreen=false
here is my code and it a garbage.
static int beautifulDays(int i, int j, int k) {
var total = 0;
for(var a = i; a <= j; a++ )
{
if (a != 0)
{
int ri = Reverse(i);
int rj = Reverse(j);
var ra = Reverse(a);
if((ra/k) % 1 == 0)
{
total++;
}
if((rj/k) % 1 == 0)
{
total++;
}
if((ri/k) % 1 == 0)
{
total++;
}
}
return total;
}
return total;
}
public static int Reverse(int inval)
{
int result = 0;
do
{
result = (result * 10) + (inval % 10);
inval = inval / 10;
}
while(inval > 0);
return result;
}
simply, can you give me the answer of HackerRank "Beautiful Days at the Movies".
link below.
https://www.hackerrank.com/challenges/beautiful-days-at-the-movies/problem?isFullScreen=false

Using Java you can easily stream a range of numbers with IntStream, then map the reverse function for each value, then filter those that fulfils the condition and count. With streams you don't need to store, you can get straight to the answer.
IntUnaryOperator reverse = (opperand) -> {
int reversed = 0;
int num = opperand;
while (num != 0) {
int digit = num % 10;
reversed = reversed * 10 + digit;
num /= 10;
}
return Math.abs(opperand - reversed);
};
return (int) IntStream.rangeClosed(i, j).map(reverse)
.filter(v -> v % k == 0).count();

Smallest Multiple

I have a code here written in C# that finds the smallest multiple by all numbers from 1 to 20. However, I find it very inefficient since the execution took awhile before producing the correct answer. I would like to know what are the different ways that I can do to improve the code. Thank You.
public static void SmallestMultiple()
{
const ushort ARRAY_SIZE = 21;
ushort[] array = new ushort[ARRAY_SIZE];
ushort check = 0;
for (uint value = 1; value < uint.MaxValue; value++)
{
for (ushort j = 1; j < ARRAY_SIZE; j++)
{
array[j] = j;
if (value % array[j] == 0)
{
check++;
}
}
if (check == 20)
{
Console.WriteLine("The value is {0}", value);
}
else
{
check = 0;
}
}
}

static void Main(string[] args)
{
int[] nums = Enumerable.Range(1, 20).ToArray();
int lcm = 1;
for (int i = 0; i < nums.Length; i++)
{
lcm = LCM(lcm, nums[i]);
}
Console.WriteLine("LCM = {0}", lcm);
}
public static int LCM(int value1, int value2)
{
int a = Math.Abs(value1);
int b = Math.Abs(value2);
// perform division first to avoid potential overflow
a = checked((a / GCD(a, b)));
return checked((a * b));
}
public static int GCD(int value1, int value2)
{
int gcd = 1; // Greates Common Divisor
// throw exception if any value=0
if (value1 == 0 || value2 == 0)
{
throw new ArgumentOutOfRangeException();
}
// assign absolute values to local vars
int a = Math.Abs(value1); // local var1
int b = Math.Abs(value2); // local var2
// if numbers are equal return the first
if (a == b) { return a; }
// if var "b" is GCD return "b"
if (a > b && a % b == 0) { return b; }
// if var "a" is GCD return "a"
if (b > a && b % a == 0) { return a; }
// Euclid algorithm to find GCD (a,b):
// estimated maximum iterations:
// 5* (number of dec digits in smallest number)
while (b != 0)
{
gcd = b;
b = a % b;
a = gcd;
}
return gcd;
}
}
Source : Fast Integer Algorithms: Greatest Common Divisor and Least Common Multiple, .NET solution

Since the result must also be divisible by 19 (which is the greatest prime number) up to 20, you might only cycle through multiples of 19.
This should get to to the result about 19 times faster.
Here's the code that does this:
public static void SmallestMultiple()
{
const ushort ARRAY_SIZE = 21;
ushort[] array = new ushort[ARRAY_SIZE];
ushort check = 0;
for (uint value = 19; value < uint.MaxValue; value += 19)
{
for (ushort j = 1; j < ARRAY_SIZE; j++)
{
array[j] = j;
if (value % array[j] == 0)
{
check++;
}
}
if (check == 20)
{
Console.WriteLine("The value is {0}", value);
return;
}
else
{
check = 0;
}
}
}
On my machine, this finds the result 232792560 in a little over 2 seconds.
Update
Also, please note that the initial program did not stop when reaching a solution; I have added a return statement to make it stop.

You're just looking for the LCM of the numbers from 1 to 20:
Where the GCD can be efficiently calculated with the Euclidean algorithm.
I don't know C#, but this Python solution shouldn't be hard to translate:
def gcd(a, b):
while b != 0:
a, b = b, a % b
return a
def lcm(a, b):
return (a * b) / gcd(a, b)
numbers = range(1, 20 + 1)
print reduce(numbers, lcm)
It's pretty fast too:
>>> %timeit reduce(lcm, range(1, 20000))
1 loops, best of 3: 258 ms per loop

EDIT: v2.0 - Major speed improvement
Building on w0lf's solution. A faster solution:
public static void SmallestMultiple()
{
// this is a bit quick and dirty
// (not too difficult to change to generate primeProduct dynamically for any range)
int primeProduct = 2*3*5*7*11*13*17*19;
for (int value = primeProduct; ; value += primeProduct)
{
bool success = true;
for (int j = 11; j < 21; j++)
{
if (value % j != 0)
{
success = false;
break;
}
}
if (success)
{
Console.WriteLine("The value is {0}", value);
break;
}
}
}
You needn't check 1-10 since if something is divisible by x (e.g. 12), it is divisible by x/n (e.g. 12/2 = 6). The smallest multiple will always be a multiple of a product of all the primes involved.
Didn't benchmark C# solution, but equivalent Java solution runs in about 0.0000006 seconds.

Well I'm not sure what exactly you are trying to accomplish here but your out side for loop will run approximately 4,294,967,295 time (uint.MaxValue). So that will take some time...
If you have a way to keep from going to uint.MaxValue - like breaking your loop when you have accomplished what you need to - that will speed it up.
Also, since you are setting array[j] equal to j and then apparently never using the array again why not just do:
value % j
instead of
value % array[j]

Using also code written by W0lf (sorry but i cannot comment on your post) I would improve it (only a little) deleting the array that I think is useless..
public static void SmallestMultiple()
{
const ushort ARRAY_SIZE = 21;
ushort check = 0;
for (uint value = 1; value < uint.MaxValue; value++)
{
for (ushort j = 1; j < ARRAY_SIZE; j++)
{
if (value % j == 0)
{
check++;
}
}
if (check == 20)
{
Console.WriteLine("The value is {0}", value);
}
else
{
check = 0;
}
}
}

Special Counters

I`m trying to create a special counter in C# ... I mean the counter will be consisting of characters not numbers.
I have a char[] of size 3:
char[] str = new char[strSize];
int i = 0;
int tmpSize = strSize - 1;
int curr;
while(!isEqual(str,finalStr,strSize))
{
str[strSize] = element[i % element.Length];
i++;
if (str[strSize] == element[element.Length - 1])
{
int j = strSize - 1;
if (j > 0)
{
j--;
int tmpCntr = j+1;
curr = getCurrentID(str[tmpCntr]);
str[tmpCntr] = element[(curr + 1) % element.Length];
while (str[tmpCntr] == element[0] && (i % element.Length > 0) && tmpCntr < 0)
{
tmpCntr--;
curr = getCurrentID(str[tmpCntr]);
str[tmpCntr] = element[(curr + 1) % element.Length];
}
}
}
}
if the strSize < 3 the application works fine and gives accurate output. If the strSize >= 3, the application goes in infinite loop!
Need help.
if this is hard this way, I would need a way to create a numerical counter and I`ll work on it to suite my application.

You haven't shown what half of your methods or parameters are.
Personally I would take a different approach. I would use an iterator block to make it easy to return an IEnumerable<string>, and internally just keep an integer counter. Then you just need to write a method to convert a counter value and "alphabet of digits" into a string. Something like this:
public static IEnumerable<string> Counter(string digits, int digitCount)
{
long max = (long) Math.Pow(digits.Length, digitCount);
for (long i = 0; i < max; i++)
{
yield return ConvertToString(i, digits, digitCount);
}
}
Another alternative is to do the same thing with LINQ, if a range of int is enough:
public static IEnumerable<string> Counter(string digits, int digitCount)
{
int max = (int) Math.Pow(digits.Length, digitCount);
return Enumerable.Range(0, max)
.Select(i => ConvertToString(i, digits, digitCount));
}
In either case, you just iterate over the returned sequence to get appropriate counter values.
With those in place, you just need to implement ConvertToString - which would probably be something like this:
public static string ConvertToString(long value, string digits, int digitCount)
{
char[] chars = new char[digitCount];
for (int i = digitCount - 1 ; i >= 0; i--)
{
chars[i] = digits[(int)(value % digits.Length)];
value = value / digits.Length;
}
return new string(chars);
}
Here's a test program showing it all working:
using System;
using System.Collections.Generic;
using System.Linq;
class Test
{
static void Main()
{
// Show the first 10 values
foreach (string value in Counter("ABCD", 3).Take(10))
{
Console.WriteLine(value);
}
}
public static IEnumerable<string> Counter(string digits, int digitCount)
{
long max = (long) Math.Pow(digits.Length, digitCount);
for (long i = 0; i < max; i++)
{
yield return ConvertToString(i, digits, digitCount);
}
}
public static string ConvertToString(long value,
string digits,
int digitCount)
{
char[] chars = new char[digitCount];
for (int i = digitCount - 1 ; i >= 0; i--)
{
chars[i] = digits[(int)(value % digits.Length)];
value = value / digits.Length;
}
return new string(chars);
}
}
Output:
AAA
AAB
AAC
AAD
ABA
ABB
ABC
ABD
ACA
ACB