[백준] 22865번 가장 먼 곳 (파이썬)

https://www.acmicpc.net/problem/22865

import sys
import heapq

input = sys.stdin.readline

n = int(input())
a, b, c = map(int, input().split())
m = int(input())
graph = [[] for _ in range(n+1)]
for _ in range(m):
    d, e, l = map(int, input().split())
    graph[d].append((e, l))
    graph[e].append((d, l))

INF = float('inf')

def dijkstra(start):
    distance = [INF]*(n+1)
    
    q = []
    heapq.heappush(q, (0, start))
    distance[start] = 0

    while q:
        dist, now = heapq.heappop(q)
        if distance[now] < dist:
            continue

        for i in graph[now]:
            cost = dist + i[1]
            if cost < distance[i[0]]:
                distance[i[0]] = cost
                heapq.heappush(q, (cost, i[0]))

    return distance

a_dist = dijkstra(a)
b_dist = dijkstra(b)
c_dist = dijkstra(c)

result = []
for i in range(1, n+1):
    m = min(a_dist[i], b_dist[i], c_dist[i])
    result.append(m)
M = max(result)
print(result.index(M) + 1)