الخوارزميات الجشعة وأقصر مسار

def greedy_change(coins, amount):    used = []    for c in sorted(coins, reverse=True):     # الأكبر أولًا        while amount >= c:            amount -= c            used.append(c)    return used print(greedy_change([1, 5, 10, 50, 100], 167))   # الريالات: صحيحprint(greedy_change([1, 3, 4], 6))               # خطأ! الأمثل [3, 3]

bookings = [("ورشة Excel", 8, 10), ("اجتماع", 9, 11), ("محاضرة", 10, 12),            ("مقابلة", 11, 12), ("تدريب", 12, 14), ("زيارة", 13, 15), ("دورة", 14, 16)] chosen = []end = 0for name, s, e in sorted(bookings, key=lambda b: b[2]):   # الأبكر انتهاءً أولًا    if s >= end:        chosen.append(name)        end = eprint(len(chosen), chosen)

roads = [("المدينة", "ينبع", 230), ("المدينة", "بدر", 150), ("ينبع", "رابغ", 180),         ("بدر", "رابغ", 120), ("رابغ", "جدة", 150), ("جدة", "مكة", 80),         ("مكة", "الطائف", 90), ("بدر", "مكة", 330)]graph = {}for a, b, km in roads:    graph.setdefault(a, []).append((b, km))    graph.setdefault(b, []).append((a, km))import heapq def dijkstra(start):    dist = {start: 0}    parent = {start: None}    heap = [(0, start)]    done = set()    while heap:        d, city = heapq.heappop(heap)        # أقرب مدينة لم تُحسم بعد        if city in done:            continue        done.add(city)        for nb, km in graph[city]:            nd = d + km            if nd < dist.get(nb, float("inf")):   # وجدنا طريقًا أقصر                dist[nb] = nd                parent[nb] = city                heapq.heappush(heap, (nd, nb))    return dist, parent def path_to(parent, goal):    p = []    while goal is not None:        p.append(goal)        goal = parent[goal]    return p[::-1] dist, parent = dijkstra("المدينة")for city in sorted(dist, key=dist.get):    print(f"{city}: {dist[city]} كم ← " + " ← ".join(path_to(parent, city)))