Skip to content

Latest commit

 

History

History
14 lines (12 loc) · 861 Bytes

Interview Questions.md

File metadata and controls

14 lines (12 loc) · 861 Bytes
Raw

Interview Questions: Hash Tables (ungraded)

TOTAL POINTS 2

Question 1

4-SUM.

Given an array a[] of n integers, the 4-SUM problem is to determine if there exist distinct indices i, j, k, and l such that a[i] + a[j] = a[k] + a[l]. Design an algorithm for the 4-SUM problem that takes time proportional to n^2 (under suitable technical assumptions).

Question 2

Hashing with wrong hashCode() or equals().

Suppose that you implement a data type OlympicAthlete for use in a java.util.HashMap.

  • Describe what happens if you override hashCode() but not equals().
  • Describe what happens if you override equals() but not hashCode().
  • Describe what happens if you override hashCode() but implement public boolean equals(OlympicAthlete that) instead of public boolean equals(Object that).