Untitled

# Banker's Algorithm

def bankers_algorithm(alloc, max_need, avail):
    n = len(alloc)  # number of processes
    m = len(avail)  # number of resources

    need = [[max_need[i][j] - alloc[i][j] for j in range(m)] for i in range(n)]
    finish = [0] * n
    safe_seq = []

    work = avail[:]

    while len(safe_seq) < n:
        found = False
        for i in range(n):
            if not finish[i] and all(need[i][j] <= work[j] for j in range(m)):
                for j in range(m):
                    work[j] += alloc[i][j]
                safe_seq.append(i)
                finish[i] = 1
                found = True
        if not found:
            print("System is not in safe state.")
            return
    print("System is in safe state.\nSafe sequence:", ' → '.join('P'+str(i) for i in safe_seq))


# Example Input
alloc = [[0, 1, 0],
         [2, 0, 0],
         [3, 0, 2],
         [2, 1, 1],
         [0, 0, 2]]

max_need = [[7, 5, 3],
            [3, 2, 2],
            [9, 0, 2],
            [2, 2, 2],
            [4, 3, 3]]

avail = [3, 3, 2]

bankers_algorithm(alloc, max_need, avail)

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# Bully Algorithm

def bully_algorithm(processes, crashed, initiator):
    alive = [p for p in processes if p not in crashed]
    print(f"Processes alive: {alive}")
    print(f"Process {initiator} starts election...")

    higher = [p for p in alive if p > initiator]
    if not higher:
        print(f"Process {initiator} becomes the Coordinator.")
    else:
        for p in higher:
            print(f"Process {initiator} sends election message to {p}")
        new_coordinator = max(higher)
        print(f"Process {new_coordinator} becomes the Coordinator.")

# Example
processes = [1, 2, 3, 4, 5]
crashed = [5]       # crashed process
initiator = 3        # who starts the election

bully_algorithm(processes, crashed, initiator)
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# Ring Election Algorithm

def ring_algorithm(processes, initiator):
    print(f"Processes in ring: {processes}")
    print(f"Process {initiator} starts the election...")

    index = processes.index(initiator)
    msg = [initiator]

    # Pass message around the ring
    for i in range(1, len(processes)):
        next_process = processes[(index + i) % len(processes)]
        print(f"Message passed from {msg[-1]} to {next_process}")
        msg.append(next_process)

    coordinator = max(processes)
    print(f"Process {coordinator} becomes the Coordinator.")

# Example
processes = [1, 2, 3, 4, 5]
initiator = 2

ring_algorithm(processes, initiator)

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