I would like to write some algorithms to train with new knowleges in C#.
All sources, tests, etc... available here: https://github.com/AGanyushkin/AlgoTrainer
What we need to do: move all zero elements to the end of the array.
also required:
[ 0, 7, 3, 0, 1 ] -> [ 7, 3, 1, 0, 0 ]
My solution:
Main idea - from left to right, we trying to find '0' (position 1). Then find first non-zero (position 2) after that position (position 1) and swap position 1 and position 2.
public int[] toDo(int[] inputArray)
{
for (int i = 0; i < inputArray.Length; i++)
{
if (inputArray[i] != 0) continue;
bool hasSwap = false;
for (int j = i + 1; j < inputArray.Length; j++)
{
if (inputArray[j] != 0)
{
var tmp = inputArray[i];
inputArray[i] = inputArray[j];
inputArray[j] = tmp;
hasSwap = true;
break;
}
}
if (!hasSwap) break;
}
return inputArray;
}
What we need to do: calculate num of characters in sequences.
"abbbnnnm" -> "a1b3n3m1"
My solution:
Main idea - iterate from left to right. Save current character and increase counter. if there is new character in input - put result into output and save new state.
public string toDo(string inputString)
{
if (inputString.Length == 0) return "";
if (inputString.Length == 1) return $"{inputString}1";
StringBuilder builder = new();
char current = inputString[0];
byte counter = 1;
for(int i = 1; i < inputString.Length; i++)
{
if (inputString[i] != current)
{
builder
.Append(current)
.Append(counter);
current = inputString[i];
counter = 1;
}
else
{
counter += 1;
}
}
builder
.Append(current)
.Append(counter);
return builder.ToString();
}
Return TRUE if two string are anagrams of each other.
"aba" & "aab" -> true
My solution:
Main idea - calculate counters for each character. with "+" from first input and with "-" from second input.
If in result counters we have for all counters value == 0 it means this is an anograms.
public bool toDo(string firstInputString, string secondInputString)
{
if (firstInputString == secondInputString) return true;
if (firstInputString.Length != secondInputString.Length) return false;
Dictionary<char, short> accumulator = new ();
for (int i = 0; i < firstInputString.Length; i++)
{
char ch;
ch = firstInputString[i];
if (accumulator.ContainsKey(ch))
accumulator[ch] += 1;
else
accumulator[ch] = 1;
ch = secondInputString[i];
if (accumulator.ContainsKey(ch))
accumulator[ch] -= 1;
else
accumulator[ch] = -1;
}
foreach(var v in accumulator.Values)
{
if (v != 0) return false;
}
return true;
}
That's all :)