aoc2021/aoc18 at main · herczyn/aoc2021 · GitHub

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arr = document.getElementsByTagName("pre")[0].innerText.split("\n").filter(function(n){return n;});

print = function(snail) {
	if (Array.isArray(snail)) {
		return "[" + print(snail[0]) + "," + print(snail[1]) + "]";
	}
	return snail;
}

increaseLeft = function(s, amount) {
	if (amount == 0) {
		return s;
	}
	if (Array.isArray(s)) {
		return [increaseLeft(s[0], amount), s[1]];
	}
	return s+amount;
}

increaseRight = function(s, amount) {
	if (amount == 0) {
		return s;
	}
	if (Array.isArray(s)) {
		return [s[0], increaseRight(s[1], amount)];
	}
	return s+amount;
}

explode = function(snail, depth) {
	if (depth<3 && Array.isArray(snail)) {
		left = explode(snail[0], depth+1);
		if (left[1]) {
			return [[left[0], increaseLeft(snail[1], left[3])], left[1], left[2], 0];
		}
		right = explode(snail[1], depth+1);
		if (right[1]) {
			return [[increaseRight(snail[0], right[2]), right[0]], right[1], 0, right[3]];
		}
		return [snail, false];
	}
	if (depth==3 && Array.isArray(snail)) {
		if (Array.isArray(snail[0])) {
			return [[0, increaseLeft(snail[1], snail[0][1])], true, snail[0][0], 0];
		}
		if (Array.isArray(snail[1])) {
			return [[increaseRight(snail[0], snail[1][0]), 0], true, 0, snail[1][1]];
		}
	}
	return [snail, false]
}

split = function(snail) {
	if (Array.isArray(snail)) {
		left = split(snail[0]);
		if (left[1]) {
			return [[left[0], snail[1]], true];
		}
		right = split(snail[1]);
		if (right[1]) {
			return [[snail[0], right[0]], true];
		}
		return [snail, false];
	}
	if (snail > 9) {
		return [[Math.floor(snail/2), Math.ceil(snail/2)], true]
	}
	return [snail, false];
}

add = function(snail1, snail2) {
	snail = [snail1, snail2];
	while (true) {
		explodeResult = explode(snail, 0);
		if (explodeResult[1]) {
			snail = explodeResult[0];
		} else {
			splitResult = split(snail);
			if (splitResult[1]) {
				snail = splitResult[0];
			} else {
				break;
			}
		}
	}
	return snail;
}
//snail = eval(arr[0]);
//for (i=1; i<arr.length; i++) {
//	snail = add(snail, eval(arr[i]));
//}

magnitude = function(snail) {
	if (Array.isArray(snail)) {
		return magnitude(snail[0]) * 3 + magnitude(snail[1]) * 2;
	}
	return snail;
}
maxMag = 0;
for (i=0; i<arr.length; i++) {
	for(j=0; j<arr.length; j++) {
		if (i!=j) {
			snail = add(eval(arr[i]), eval(arr[j]));
			mag = magnitude(snail);
			if (mag > maxMag) {
				maxMag = mag;
			}
		}
	}
}
maxMag