Files
snk/packages/compute/getBestRoute.ts
2020-07-30 18:33:42 +02:00

153 lines
3.2 KiB
TypeScript

import { Grid, Color, copyGrid, getColor, setColor } from "./grid";
import { Point } from "./point";
import { Snake } from "./snake";
import { getAvailableRoutes } from "./getAvailableRoutes";
const isGridEmpty = (grid: Grid) => grid.data.every((x) => x === null);
const createComputeHeuristic = (
grid0: Grid,
_snake0: Snake,
colors: Color[]
) => {
const colorCount: Record<Color, number> = {};
for (let x = grid0.width; x--; )
for (let y = grid0.height; y--; ) {
const c = getColor(grid0, x, y);
if (c !== null) colorCount[c] = 1 + (colorCount[c] || 0);
}
const values = colors
.map((k) => Array.from({ length: colorCount[k] }, () => k))
.flat();
return (_grid: Grid, _snake: Snake, stack: Color[]) => {
let score = 0;
for (let i = 0; i < stack.length; i++) {
if (stack[i] === values[i]) {
score += 52;
} else {
const u = Math.abs(stack[i] - values[i]);
score += 5 - u;
}
}
return score;
};
};
const computeKey = (grid: Grid, snake: Snake, stack: Color[]) =>
grid.data.map((x) => x || 0).join("") +
"|" +
snake.map((p) => p.x + "." + p.y).join(",") +
"|" +
stack.join("");
type I = {
h: number;
f: number;
w: number;
key: string;
snake: Snake;
grid: Grid;
stack: Color[];
parent: I | null;
directions: Point[];
};
export const getBestRoute = (
grid0: Grid,
snake0: Snake,
options: { maxSnakeLength: number; colors: Color[] },
maxIterations = 500
) => {
const computeHeuristic = createComputeHeuristic(
grid0,
snake0,
options.colors
);
const closeList: Record<string, I> = {};
const openList: I[] = [];
{
const h = computeHeuristic(grid0, snake0, []);
const w = 0;
const f = h + w;
openList.push({
key: computeKey(grid0, snake0, []),
grid: grid0,
snake: snake0,
stack: [],
parent: null,
f,
h,
w,
directions: [],
});
}
let best = openList[0];
while (openList.length && maxIterations-- > 0) {
openList.sort((a, b) => a.f - b.f);
const c = openList.shift()!;
closeList[c.key] = c;
if (c.f < best.f) best = c;
if (!isGridEmpty(c.grid)) {
const availableRoutes = getAvailableRoutes(
c.grid,
c.snake,
options,
30,
1,
20,
500
);
for (const route of availableRoutes) {
const stack = c.stack.slice();
const grid = copyGrid(c.grid);
const snake = route.snakeN;
const { x, y } = route.snakeN[0];
stack.push(getColor(grid, x, y)!);
setColor(grid, x, y, null);
const key = computeKey(grid, snake, stack);
if (!closeList[key] && !openList.some((s) => s.key === key)) {
const h = computeHeuristic(grid, snake, stack);
const w = c.w + route.directions.length;
const f = w - h;
openList.push({
key,
grid,
snake,
stack,
parent: c,
h,
w,
f,
directions: route.directions,
});
}
}
}
}
return unwrap(best);
};
const unwrap = (o: I | null): Point[] => {
if (!o) return [];
return [...unwrap(o.parent), ...o.directions];
};