[백준] 1446번 지름길 (파이썬)

https://www.acmicpc.net/problem/1446

import heapq

n, d = map(int, input().split())
graph = [[] for _ in range(d+1)]
for _ in range(n):
    a, b, c = map(int, input().split())
    if b > d:
        continue
    graph[a].append((b, c))
for i in range(d):
    graph[i].append((i+1, 1))
    
INF = float('inf')
distance = [INF]*(d+1)

def dijkstra(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]))

dijkstra(0)
print(distance[d])