LeetCode Weekly Contest 195 Swift Solutions

Array subsequences feature!

Photo by Art Lasovsky on Unsplash

This article is about the 4 challenges in the LeetCode Weekly Contest 195. That is

• 1496 Path Crossing
• 1497 Check If Array Pairs Are Divisible by k
• 1498 Number of Subsequences That Satisfy the Given Sum Condition
• 1499 Max Value of Equation

The solutions assume some knowledge of Big O notation

The Problems

Each problem will be approached in turn, with a solution and also with articles explaining the tools, techniques and theory that will help you solve these problems yourself.

Let us get started!

1496. Path Crossing

I have used some knowledge of Strings and Characters in Swift to make this solution a little faster.

Given a String of paths represented as the single characters ‘N, ‘S’, ‘E’ and ‘W’ a path is formed from the origin (0,0) where ‘N, ‘S’, ‘E’ and ‘W’ represent moving up, down, east and west respectively.

I decided to represent each location as a pair (and since there will be comparisons this will need to conform to Hashable resulting in

struct Pair: Hashable {
    var…