다익스트라

시간복잡도: O(ElogV)

E: 간선, V: 노드 갯수 E <= V^2

O(ElogE) <= O(ElogV^2) == O(2ElogV)

 

import heapq
import sys
INF = int(1e9)

input = sys.stdin.readline
n, m = map(int, input().split())
start = int(input())
graph = [[] for i in range(n+1)]
distance = [INF]*(n+1)
for _ in range(m):
    a, b, c = map(int, input().split())
    graph[a].append((b,c))

def dijk(start):
    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]))
dijk(start)

for i in range(1, n+1):
    if distance[i] == INF:
        print("INF")
    else:
        print(distance[i])