mgia / piscine-interview

Technical Interview Bootcamp

Piscine Starfleet: Technical Interview Bootcamp

This two-week bootcamp teaches the fundementals of computational thinking and prepares participant for a functional role at an organisation.

In essence, the content covered is equivalent to two years of Computer Science modules at any major university.

Topics

Over the course of 8 days of assignments, the following topics were covered:

• Big O Notation
• Searching Algorithms
• Sorting Algorithms
• Bit Manipulation
• Recursive Algorithms
• Data structures (Arrays, Linked Lists, Binary Trees, Graphs)

Notes

For reference, time complexity usually refers to the amount of time a program (i.e. a set of functions) take to run. This is computed based on how data structures, like arrays, are traversed and modified. For example:

A program counts the number of characters in a string and returns the count. (e.g. "hello world" => 11)
This is done by running through each character and incrementing a counter.

function countCharacters(char *str)
{
  int count;
  
  count = 0;
  while (*str)
  {
    count++;
    str++;
  }
  return (count);
}

The runtime grows linearly with the number of characters, thus we say that the time complexity is O(n).

In comparison:

A program checks, for each character, if the character was repeated in the string and substitutes the
character with 1 or 0. (e.g. hello world => "00111001010")

function checkRepeats(char *str)
{
  int i;
  int j;
  
  i = 0;
  while (str[i])
  {
    j = 0;
    while (str[j])
    {
      if (j != i && str[j] == str[i])
      { 
        str[i] = '1';
        break ;
       }
    }
    if (str[i] != '1')
      str[i] = '0';
    i++;
  }
}

In this case, we traverse the entire array for each character. Therefore, the runtime will be the length of the the array multipled by the length of the array, thus we say the time complexity is O(n²).

Score

90/100