Introduction

Algorithmic Problems

  • Decision problems: yes/no
    • Given a graph G, is G connected?
    • Given a graph G, is G 3-colorable?
    • Given a boolean formula phi, is phi satisfiable?
    • Given a natural number M, is M a prime?
  • Function problems
    • Given 2 integers M and N, find the GCD
    • Given a network of cities and distances, find the length of minimal length
  • Enumeration problems
    • Given a natural number, find its prime factors
    • Given a boolean formula phi, find all/how many satisfying assortments
  • Optimization problems
    • Given a network of cities and distances, find a tour of minimal length

In general, decision problems are the easiest to solve - and any problem can be expressed as a series of decision problems

Problem Difficulties

  • Unsolvable
  • Solvable
    • Untractable (NP runtime)
    • Tractable (polynomial runtime)