vishnoitanuj / Interview_prep

Notes

Time Complexity Analysis

Big O A -> f(n) if time taken by A for input n <= k*f(n)

Insertion Sort

• Worst Case Complexity: O(n^2)
• Best Case Complexity: O(n)

Selection Sort

• Worst Case Complexity: O(n^2)
• Best Case Complexity: O(n^2)

Merge Sort

• O(nlogn) --> base is 2
• Space Complexity O(n)

Binary Search

• Time Complexity is O(logn) --> base is 2
• Space Complexity in recurive algo is O(logn)

Bubble Sort

• Space Complexity is O(1)

Space Complexity Analysis

• Calculate auxilliary space required.
• Max space requirement at any point of time.
• Space complexity for finding nth fibonacci number using recurion is O(n)

Arrays

• Whenever an integer array is created, all elements are initialised to 0.
• Whenever an boolean array is created, all elements are initialised to false.
• Whenever a double array is created, all elements are initialised to 0.0 . Whenever we just print name of array, eg. sopln(a) -> [I@42a5773]. >>* [ = We are talking about arrays >>* I = integer array >>* after @ = hexadecimal memory address reference of array
• Java has a garbage collector collector which runs periodically and destroys assigned memory locations which are not being used.
• Passsing primitive and non-primitive data in functions varies output. In primitive the changes in value caused in function does not change the main value. But in non-primitive, like arrays, the reference of array is passed, so any changes made in values of array in function reflects in main array too.