samrith-s / nearest-neighbour

A simple nearest neighbour solution in TypeScript

Nearest Neighbour

A simple nearest neighbour solution in TypeScript.

Table of contents

• Problem statement
• Considerations
• Other considerations
  • Solution 1
  • Solution 2
• Commands
• Inputs

Problem statement

Write a program which:

• reads the description of the bitmap from the standard input
• for each pixel, computes the distance to the nearest white
• writes the results to the standard output

Considerations

A rectangular bitmap with only black and white pixels. Atleast ONE pixel is white. All black pixels are represented by 0 and whites by 1.

• Size: n * m
• Size constraints:: 1<=n <=182, 1<=m<=182
• Pixel: p(i,j)
• Distance formula: d(p1,p2) = |i1-i1|+|j1-j2|

Other considerations

Since the problem does not explicitly mention how to find the nearest neighbour, this program addresses two solutions based on the example output provided.

Solution 1

The first solution scans within the same row and tries to find the closest white pixel, like so:

Solution 2

The second solution scans in all four directions and tries to find the closest white pixel, like so:

Commands

• yarn dev:one - Run the first solution in dev mode
• yarn dev:two - Run the second solution in dev mode
• yarn build - Build both solutions
• yarn start:one < path/to/file.txt - Run the production build using solution one
• yarn start:two < path/to/file.txt - Run the production build using solution two
• yarn lint - Lint all files and check for errors
• yarn test - Run all test suites
• yarn test:generate - Generate a random new input file in the generated folder

Inputs

All the various input files are located tests/inputs folder. You can optionally generate a random file and run it against any solution