Computer Systems

Was pretty busy today with some annex stuff, but read up on the difference between static and dynamic linking in the context of program loaders.

Key points were:

• Static linking refers to any linking that happens before runtime
• Dynamic liking refers to any linking that happens during runtime
• One of the responsibilities of the program loader is to handle any required dynamic linking (for example to standard libraries)
• The advantages of dynamic linking are:
  • easier updates (no need to recompile all dependent programs)
  • and more importantly (in my opinion) to reduce executable size, saving memory both on the drive and RAM

Leetcode

Revisited problems

974. Subarray Sums Divisible by K

Concepts: Prefix Sum, HashTable

Good introductory problem if new to prefix sums.

322. Coin Change

Concepts: Dynamic Programming

Was one of the problems I had to solve in my interviews for Modjo. Good dynamic programming problem to ask your non-CS friends!

539. Minimum Time Difference

Concepts: Array, Sorting, String

Pretty easy question, only challenging part is handling edge case to calculate time difference between 23:00 and 01:00.

523. Continuous Subarray Sum

Concepts: Prefix Sum

Similar to Subarray Sums Divisible by K.