최소 신장 트리를 구한다. 크루스칼 알고리즘을 통해 구현했다.
import sys
import heapq
n = int(sys.stdin.readline().rstrip())
m = int(sys.stdin.readline().rstrip())
pq = []
parents = [i for i in range(n+1)]
for _ in range(m):
    a, b, c = map(int, sys.stdin.readline().rstrip().split())
    heapq.heappush(pq, [c, a, b])
def find(node):
    if parents[node] == node: return node
    else:
        parents[node] = find(parents[node])
        return parents[node]
def union(node1, node2):
    root1, root2 = find(node1), find(node2)
    if root1 == root2: return False
    else:
        parents[root2] = root1
        return True
total = 0
while pq:
    c, a, b = heapq.heappop(pq)
    if union(a, b):
        total += c
print(total)