added dijkstra.py file to utils

This commit is contained in:
Toby Lane 2024-06-30 00:08:20 +02:00
parent 075ac738e4
commit ff2c184c65
2 changed files with 87 additions and 1 deletions

86
utils/dijkstra.py Normal file
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@ -0,0 +1,86 @@
from math import inf
class Edge:
length = 0
def __init__(self, start, end, length):
self.length = length
self.start = start
self.end = end
class Node:
def __init__(self, xpos, ypos):
self.xpos = xpos
self.ypos = ypos
class Graph:
def __init__(self):
self.edges = list()
self.nodes = list()
def add_node(self, xpos, ypos):
self.nodes.append(Node(xpos, ypos))
def add_edge(self, start_index, end_index, length):
self.edges.append(Edge(start_index, end_index, length))
def Dijkstra(graph, source_index, target_index):
n = len(graph.nodes)
if (target_index >= n):
return None
unvisited = list(range(n))
distances_from_start = [inf] * n
distances_from_start[source_index] = 0
node_sequences = [list() for i in range(n)]
node_sequences[source_index] = [source_index]
while(True):
try:
current_index = min(unvisited, key = lambda i: distances_from_start[i])
except ValueError:
break
if current_index == target_index:
break
unvisited.remove(current_index)
for edge in filter(
lambda e: e.start == current_index or e.end == current_index,
graph.edges):
start = current_index
end = edge.end if edge.start == current_index else edge.start
if end in unvisited and distances_from_start[end] > distances_from_start[start] + edge.length:
distances_from_start[end] = distances_from_start[start] + edge.length
node_sequences[end] = node_sequences[start].copy()
node_sequences[end].append(end)
return node_sequences[target_index]
graph = Graph()
graph.add_node(1, 2)
graph.add_node(4, 7)
graph.add_node(3,1)
graph.add_node(-2,0)
graph.add_node(0,0)
graph.add_edge(0, 1, 1)
graph.add_edge(1, 2, 2)
graph.add_edge(2, 3, 3)
graph.add_edge(3, 0, 1)
graph.add_edge(1, 3, 3)
print(Dijkstra(graph, 0, 5))

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@ -13,7 +13,7 @@ def clamp(mn, value, mx):
def main():
# 2024-06-27_21.01.45_Lycacraft_minecraft~overworld_day.png
# utils/2024-06-27_21.01.45_Lycacraft_minecraft~overworld_day.png
# 6144,10240
input_path = input("Input image: ")
output_path = input(f"Output dir (default: {DEFAULT_PATH}): ")