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Posted on Sep 8, 2020

Daily Challenge #289 - Manhattan Distance

#challenge

The distance formula can be used to find the distance between two points. What if we were trying to walk from point A to point B, but there were buildings in the way? We would need some other formula, but which?

Manhattan Distance
Manhattan distance is the distance between two points in a grid (like the grid-like street geography of the New York borough of Manhattan) calculated by only taking a vertical and/or horizontal path.

Write a function manhattanDistance that accepts two points, pointA and pointB, and returns the Manhattan Distance between the two points.

pointA and pointB are arrays containing the x and y coordinate in the grid. You can think of x as the row in the grid, and y as the column.

Examples:
manhattanDistance( [1, 1], [1, 1] ) // => returns 0
manhattanDistance( [5, 4], [3, 2] ) // => returns 4
manhattanDistance( [1, 1], [0, 3] ) // => returns 3

Tests:
manhattanDistance( [1,2], [1,3] )
manhattanDistance( [5,2], [7,3] )
manhattanDistance( [1,2], [4,4] )

Good luck!

This challenge comes from xDranik on CodeWars. Thank you to CodeWars, who has licensed redistribution of this challenge under the 2-Clause BSD License!

Want to propose a challenge idea for a future post? Email yo+challenge@dev.to with your suggestions!

Top comments (6)

Mihail Malo • Sep 8 '20

JavaScript

const manhattan = ([x1, y1], [x2, y2]) => Math.abs(x2-x1) + Math.abs(y2-y1)

Patrick Tingen • Sep 9 '20 • Edited

Progress 4GL (aka OpenEdge ABL)

FUNCTION manhattan RETURNS INTEGER
  ( x1 AS INTEGER, y1 AS INTEGER
  , x2 AS INTEGER, y2 AS INTEGER):

  RETURN ABS(x2 - x1) + ABS(y2 - y1).

END FUNCTION. 

MESSAGE manhattan(5,2,7,3)
  VIEW-AS ALERT-BOX INFORMATION BUTTONS OK.

Mihail Malo • Sep 8 '20 • Edited

Rust

lol generics

use core::ops::{Add, Sub};
fn abs_difference<T>(x: T, y: T) -> T
where
    T: Sub<Output = T> + Ord,
{
    if x < y {
        y - x
    } else {
        x - y
    }
}

struct Point<T>(T, T);

fn manhattan<T>(Point(x1, y1): Point<T>, Point(x2, y2): Point<T>) -> T
where
    T: Sub<Output = T> + Add<Output = T> + Ord,
{
    abs_difference(x2, x1) + abs_difference(y2, y1)
}

fn main() {
    assert_eq!(manhattan(Point(1, 1), Point(1, 1)), 0);
    assert_eq!(manhattan(Point(5, 4), Point(3, 2)), 4);
    assert_eq!(manhattan(Point(1, 1), Point(0, 3)), 3);

    dbg!(manhattan(Point(1, 2), Point(1, 3)));
    dbg!(manhattan(Point(5, 2), Point(7, 3)));
    dbg!(manhattan(Point(1, 2), Point(4, 4)));
}

peter279k • Sep 9 '20

Here is the simple solution with Python:

def manhattan_distance(pointA, pointB):
    return abs(pointA[0] - pointB[0]) + abs(pointA[1] - pointB[1])

Jérémie Bardon • Sep 8 '20

I'm sure a most simpler solution exist but:

function calculateDistance(a, b) {
    return a.map((d1, index) => {
        return Math.abs(d1 - b[index])
    }).reduce((acc, curr) => acc + curr);
}

Efrain Rivera • Sep 9 '20

Python

def manhattan_distance(x1, y1, x2, y2):
      distance = abs(x2 - x1) + abs(y2 - y1)
      return distance

print(manhattan_distance(5,2,7,3))

DEV Community

Daily Challenge #289 - Manhattan Distance

Top comments (6)

JavaScript

Rust

Python

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