2025(08): I misread the assignment, I think

2025/08/part1.py

@@ -0,0 +1,87 @@
+import numpy as np
+
+
+debug = False
+
+def load_junctions(filename: str):
+	"""
+	Load junction file into memory.
+	"""
+	data = np.loadtxt(filename, dtype=int, delimiter=",")
+
+	return data
+
+def distances(junctions, sorted=True):
+	"""
+	Use the upper triangle to calculate distances so we don't do it twice per
+	pair.
+	
+	NOTE: The upper triangle includes the pairs of each junction with itself.
+	"""
+	jlen = len(junctions)
+	X, Y = np.triu_indices(jlen)
+
+	# Ignore distances if x == y.
+	non_self_identities = X != Y
+	X = X[non_self_identities]
+	Y = Y[non_self_identities]
+
+	# NOTE: I do note use np.zeros_like as I want the dtype to be the default (float).
+	dists = np.zeros(X.shape)
+
+	# For each pair, calculate the distance.
+	for i in range(len(X)):
+		x, y = X[i], Y[i]
+		dists[i] = np.linalg.norm(junctions[x] - junctions[y])
+	
+	# Sort the distances, X, and Y from shortest to longest distance.
+	if sorted:
+		sorted_indices = np.argsort(dists)
+		X = X[sorted_indices]
+		Y = Y[sorted_indices]
+		dists = dists[sorted_indices]
+
+	return X, Y, dists
+
+def num_of_combinations(length):
+	return length*(length - 1)//2
+
+def is_connected(x, connections):
+	for connection in connections:
+		if x in connection:
+			return True
+	return False
+
+def get_circuits(junctions, connections):
+	"""
+	Convert connections into circuits.
+
+	Start by adding all junction indices as circuits, then iterating over
+	connection to make disjunct sets.
+	"""
+	# circuits = [[x] for x in range(len(junctions))]
+	circuits = [list(x) for x in connections]
+	changed = True
+	while changed:
+		changed = False
+		for i in range(len(circuits)):
+			for j in range(i + 1, len(circuits)):
+				for x in circuits[i]:
+					if x in circuits[j]:
+						# NOTE: Elements might appear multiple times per circuit.
+						circuits[i] += circuits.pop[j]
+						changed = True
+	return circuits
+
+
+if __name__ == "__main__":
+	test_junctions = load_junctions("testinput")
+	X, Y, dists = distances(test_junctions)
+	connections = []
+	# unconnected = list(range(len(test_junctions)))
+
+	for i in range(len(X)):
+		x, y = X[i], Y[i]
+		if not is_connected(x, connections) and not is_connected(y, connections):
+			connections.append((x, y))
+	print(len(connections))