백준 1753: 최단경로 (Python)

 

https://www.acmicpc.net/problem/1753

1753번: 최단경로

 

import heapq
import sys
input = sys.stdin.readline
INF = int(1e9)

v, e = map(int, input().split())
k = int(input())

graph = [[] for i in range(v+1)]
distance = [INF] * (v+1)

for _ in range(e):
    x, y, w = map(int, input().split())
    graph[x].append((y, w))

def dijkstra(k):
    q = []
    heapq.heappush(q, (0, k))
    distance[k] = 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]))

dijkstra(k)

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

 

정말 어이가없지ㅠ 처음에 틀려서 20분 넘게 고민했는데

무한값을 터무니없게 작게 설정해서 그런거였다ㅠ

다익스트라로 풀면 됨.!