CS Interview Question: Uncrossed Lines aka Longest Common Subsequence (LCS)

Problem Statement

We write the integers of A and B (in the order they are given) on two separate horizontal lines.

Now, we may draw connecting lines: a straight line connecting two numbers A[i] and B[j] such that:

  • A[i] == B[j];
  • The line we draw does not intersect any other connecting (non-horizontal) line.

Note that a connecting lines cannot intersect even at the endpoints: each number can…



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Most of my writing is about software. I enjoy summarizing and analyzing books and self-help videos. I am a full-time software engineer.