银行家算法模拟
作者：互联网
银行家算法（Banker's Algorithm）是一个避免死锁（Deadlock）的著名算法，是由艾兹格·迪杰斯特拉在1965年为T.H.E系统设计的一种避免死锁产生的算法。它以银行借贷系统的分配策略为基础，判断并保证系统的安全运行。----百度百科
实验要求-----从文件读取数据并输入到文件当中
由于只实现这么一个功能，干脆不分函数了，直接顺下来。
源码po出
1 available = []#资源向量
2 proc = []#进程
3 allocation = []#分配矩阵
4 max_ = []#最大需求矩阵
5 need = []#需求矩阵
6 work = []#工作向量
7 finish = []
8 wpa = []#work+allocation
9 f = open("src.txt","r+")
10 fr = f.read()
11 for i in fr:
12 if i == "\n":
13 break
14 if i != " ":
15 available.append(i)#导入Available
16 n = len(available)#资源数目
17 str1 = fr.replace("\n"," ")
18 list = str1.split(" ")
19 for i in range(n,len(list),2*n+1):
20 proc.append(list[i])#导入进程
21 tmp = 0
22 temp = n + 1
23 while temp < len(list):
24 allocation.append(list[temp])#导入Allocation
25 tmp+=1
26 temp+=1
27 if tmp == n:
28 tmp = 0
29 temp += n + 1
30 temp = 2*n+1
31 while temp < len(list):
32 max_.append(list[temp])#导入MAX
33 tmp+=1
34 temp+=1
35 if tmp == n:
36 tmp = 0
37 temp += n + 1
38 for i in range(len(max_)):
39 need.append(eval(max_[i]) - eval(allocation[i]))#计算need
40 print("从",proc,"中选择一个请求进程",end=":")
41 start = input()
42 print("输入请求的资源(共{a}个，以空格区分)".format(a=n),end=":")
43 request_t = input()
44 request = request_t.split(" ")
45 index = 0
46 for i in range(len(proc)):
47 if start == proc[i]:
48 index = i
49 break
50 flag = False
51 for i in range(n):
52 if eval(request[i]) > need[i+index*n]:#步骤1判断
53 flag = False
54 break
55 else:
56 flag = True
57 continue
58 if flag == True:
59 for i in range(n):
60 if eval(request[i]) > eval(available[i]):#步骤2判断
61 flag = False
62 break
63 else:
64 flag = True
65 continue
66 if flag == True:
67 for i in range(n):#步骤3修改资源
68 available[i] = eval(available[i]) - eval(request[i])
69 allocation[i+index*n] = eval(allocation[i+index*n]) + eval(request[i])
70 need[i+index*n] = need[i+index*n] - eval(request[i])
71 work = available
72 work_str = [0]*n*len(proc)
73 finish = [False]*len(proc)
74 for i in range(len(allocation)):
75 allocation[i] = str(allocation[i])
76 allocation[i] = eval(allocation[i])
77 queue = []#安全序列
78 for i in range(len(proc)):#安全性检查
79 for index_t in range(len(proc)):
80 if index_t not in queue:
81 if finish[index_t] == False:
82 flag_t = True
83 for j in range(n):
84 if need[j+index_t*n] > work[j]:#判断need[i][j]≤work[j]
85 flag_t = False
86 break
87 if flag_t == True:
88 for j in range(n):
89 work_str[j+index_t*n] = work[j]
90 work[j] = work[j] + allocation[j+index_t*n]
91 queue.append(index_t)
92 finish[index_t] = True
93 for i in finish:
94 if i == False:
95 flag = False
96 break
97 for i in range(len(work_str)):
98 wpa.append(work_str[i]+allocation[i])
99 if flag == True:
100 with open("yhj_res.txt","w",encoding="utf-8") as ff:
101 ff.write("\t进程\twork\tallocation\tneed\twork+allocation\tfinish\n")
102 res_list = []
103 for i in queue:
104 ff.write("\t"+str(proc[i]))
105 ff.write("\t"+str(work_str[i*n:i*n+n]))
106 ff.write("\t"+str(allocation[i*n:i*n+n]))
107 ff.write("\t"+str(need[i*n:i*n+n]))
108 ff.write("\t"+str(wpa[i*n:i*n+n]))
109 ff.write("\t "+str(finish[i])+"\n")
110 res_list.append(proc[i])
111 ff.write("可以分配，存在安全序列"+str(res_list))
112 print("可以分配，存在安全序列"+str(res_list))
113 else:
114 with open("yhj_res.txt","w",encoding="utf-8") as ff:
115 ff.write("无法分配")
116 print("无法分配")
117 f.close()
118 ff.close()
源文件内容---src.txt
其中，第一行的1 6 2 2表示给出的Available为[1,6,2,2]，后面5行的第1列表示进程的名称，根据Available的长度为4，后四列为Allocation，最后4列为Max。
1 6 2 2 a 0 0 3 2 0 0 4 4 b 1 0 0 0 2 7 5 0 c 1 3 5 4 3 6 10 10 d 0 3 3 2 0 9 8 4 e 0 0 1 4 0 6 6 10
测试
输出结果到文件yhj_res.txt
进程 work allocation need work+allocation finish a [1, 5, 1, 2] [0, 0, 3, 2] [0, 0, 1, 2] [1, 5, 4, 4] True d [1, 5, 4, 4] [0, 4, 4, 2] [0, 5, 4, 2] [1, 9, 8, 6] True e [1, 9, 8, 6] [0, 0, 1, 4] [0, 6, 5, 6] [1, 9, 9, 10] True b [1, 9, 9, 10] [1, 0, 0, 0] [1, 7, 5, 0] [2, 9, 9, 10] True c [2, 9, 9, 10] [1, 3, 5, 4] [2, 3, 5, 6] [3, 12, 14, 14] True 可以分配，存在安全序列['a', 'd', 'e', 'b', 'c']
标签：index,work,len,allocation,算法,str,True,模拟,银行家 来源： https://www.cnblogs.com/WXjzc/p/16066563.html