CalloutLandtype

One drawn region, as the outlines it is actually drawn with.

A circle keeps out of the rings themselves, so the Seto Inland Sea, Tokyo Bay and the gap between Kyushu and Shikoku are all places a number can go. A leader is only measured against the boxes around those rings, because "cross minimal number of states" is a count of places rather than a question about a coastline, and the leaders are costed thousands of times a draw.

import type { CalloutLand } from "@johnmorrisdotca/chizu";

type CalloutLand = {
    rings: readonly MapRing[];
};

import { calloutSpaces, parseMapRings, type CalloutLand } from "@johnmorrisdotca/chizu";

const island: CalloutLand = { rings: parseMapRings("M30,30L70,30L70,70L30,70Z") };
const spaces = calloutSpaces(4, { x: 0, y: 0, width: 100, height: 100 }, { bottom: 0, right: 0 }, [island]);
console.log(spaces.every((place) => !(place.x > 34 && place.x < 66 && place.y > 34 && place.y < 66)));
// true

true