Travel Plan

def solve(____):
    import heapq
    n, m, s, d = int(____), int(____), int(____), int(____)
    graph = [[] for _ in range(____)]
    for e in str(____).split(____):
        u, v, dist, cost = map(int, e.split(____))
        graph[u].append((____))
        graph[v].append((____))
    INF = float(____)
    best_d = [INF] * n
    best_c = [INF] * n
    best_d[s] = ____
    best_c[s] = ____
    pq = [(____, ____, s)]
    while pq:
        dd, cc, u = heapq.heappop(____)
        if dd > best_d[u]: continue
        for v, w, wc in graph[u]:
            nd = dd + w
            nc = cc + wc
            if nd < best_d[v] or (____):
                best_d[v] = nd
                best_c[v] = nc
                heapq.heappush(pq, (____))
    print(____)