51 lines
969 B
JavaScript
51 lines
969 B
JavaScript
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const input = (await Bun.file(Bun.argv[2]).text()).trim()
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let map = input.split("\n")
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const dirs = [[-1,0], [1,0], [0, -1], [0, 1]];
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const height = map.length;
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const width = height;
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const key = (x,y) => x + y*width;
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const visited = new Set();
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function search(x,y) {
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if (visited.has(key(x,y))) {
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return {area: 0, perimeter: 0}
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}
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visited.add(key(x,y))
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const letter = map[y][x]
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let perimeter = 0
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let area = 1
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for (const [dx, dy] of dirs) {
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const nletter = map[y + dy]?.[x + dx];
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if (letter !== nletter) {
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perimeter += 1
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continue
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}
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const n = search(x + dx, y + dy)
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area += n.area
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perimeter += n.perimeter
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}
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return {area, perimeter}
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}
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const regions = [];
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for (let y = 0; y < height; y++) {
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for (let x = 0; x < width; x++) {
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if (visited.has(key(x,y))) continue
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regions.push(search(x,y))
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}
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}
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let cost = 0
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for (const {area, perimeter} of regions) {
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cost += area * perimeter
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}
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console.log(cost)
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