file.py

import heapq as hq
import sys
import math
from typing import NamedTuple

class Entry(NamedTuple):
    cost:int
    node:int

class Solution:
    def networkDelayTime(self, times: List[List[int]], N: int, K: int) -> int:
        graph={}
        for i in range(1,N+1):
            graph[i]=[]
        for u,v,w in times:
            graph[u].append(Entry(w,v))
        
        
            
        pq = [Entry(0,K)]
        dv = [float('inf')]*N # distance vector
        dv[K-1]=0
        
        while pq:
            curr_dist,curr_node = hq.heappop(pq)
            
            for weight,endNode in graph[curr_node]:
                if dv[endNode-1] > curr_dist + weight:
                    dv[endNode-1]=curr_dist+weight
                    hq.heappush(pq,Entry(dv[endNode-1],endNode)) # must add using newly 
                    #discovered weight for ordering, this was an error
                    
        if any(math.isinf(dist) for dist in dv):
            return -1
        
        return max(dv)