commit 240c55d004f6906a16409e716c31269135108c48
parent f37e98d52336606fdc031fe93ba3a9daaeb2b219
Author: Andrew Laack <andrew@laack.co>
Date: Thu, 10 Sep 2026 10:38:55 -0500
Added prim's algorithm visualization
Diffstat:
| A | graph/prim.py | | | 123 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
1 file changed, 123 insertions(+), 0 deletions(-)
diff --git a/graph/prim.py b/graph/prim.py
@@ -0,0 +1,123 @@
+import pygame
+import time
+import heapq
+import random
+import math
+
+pygame.init()
+
+display = pygame.display.set_mode((5120,1440))
+
+VERTICES = 100
+EDGES = 200
+
+white = (255, 255, 255)
+red = (255, 0, 0)
+black = (0, 0, 0)
+grey = (100,100,100)
+light_grey = (50,50,50)
+
+
+class Vertex():
+ def __init__(self, x, y):
+ self.x = x
+ self.y = y
+ self.visited = False
+
+ def draw_vertex(self,display):
+ if self.visited:
+ pygame.draw.circle(display, white, (self.x,self.y), 5)
+ else:
+ pygame.draw.circle(display, grey, (self.x,self.y), 5)
+
+class Edge():
+ def __init__(self, v1, v2):
+ self.v1 = v1
+ self.v2 = v2
+ self.dist = math.sqrt(((v1.x - v2.x) ** 2) + ((v1.y - v2.y) ** 2))
+
+ def draw_edge(self,display, c):
+ pygame.draw.line(display, c, (self.v1.x,self.v1.y), (self.v2.x,self.v2.y), 1)
+
+ def __lt__(self,otr):
+ return self.dist < otr.dist
+
+
+while True:
+ graph = {}
+
+ for i in range(0,VERTICES):
+ x = random.random() * 5120
+ y = random.random() * 1440
+ graph[Vertex(x,y)] = []
+
+
+ edge_list = []
+ for i in range(0,EDGES):
+ k1 = None
+ k2 = None
+ while k1 == k2:
+ k1 = random.choice(list(graph.keys()))
+ k2 = random.choice(list(graph.keys()))
+
+ edge = Edge(k1,k2)
+ graph[k1].append(edge)
+ graph[k2].append(edge)
+ edge_list.append(edge)
+
+
+ edge_heap = []
+ visited_vertices = set()
+
+ mst = []
+
+ while True:
+ for event in pygame.event.get():
+ if event.type == pygame.QUIT:
+ pygame.quit()
+ quit()
+
+ display.fill(black)
+
+ for vertex in graph:
+ vertex.draw_vertex(display)
+
+ for edge in edge_list:
+ edge.draw_edge(display, light_grey)
+
+ for edge in mst:
+ edge.draw_edge(display, white)
+
+
+ if len(edge_heap) == 0:
+ start = random.choice(list(graph.keys()))
+ visited_vertices.add(start)
+ edges = graph[start]
+ for edge in edges:
+ heapq.heappush(edge_heap, edge)
+ else:
+ item = None
+ while True:
+ if len(edge_heap) > 0:
+ item = heapq.heappop(edge_heap)
+ v1_visited = item.v1 in visited_vertices
+ v2_visited = item.v2 in visited_vertices
+ if v1_visited != v2_visited:
+ break
+ else:
+ item = None
+ break
+
+ if item != None:
+ new_vertex = item.v2 if item.v1 in visited_vertices else item.v1
+ visited_vertices.add(new_vertex)
+ new_vertex.visited = True
+ mst.append(item)
+ edges = graph[new_vertex]
+ for edge in edges:
+ heapq.heappush(edge_heap, edge)
+ else:
+ pygame.image.save(display, "out.jpg")
+ break
+ time.sleep(.1)
+ pygame.display.update()
