参考java版的算法书，使用python重写了一遍。初学，自己写的，代码比较粗糙，意思明白就好。 末尾补上了字符串排序和python封装好的排序函数用法
1 import numpy as np 2 import random 3 ####验证排序算法是否正确 4 a=[x for x in range(35)] 5 random.shuffle(a) 6 print(a) 7 rank(a) ###rank为主函数 8 print(a)
接下来是不同算法实现
1 def exch(a,i,j): 2 t=a[j] 3 a[j]=a[i] 4 a[i]=t 5 ####冒泡 6 def rank(a): 7 for i in range(len(a)-1): 8 for j in range(i+1,len(a)): 9 if a[i]>a[j]: 10 exch(a,i,j) 11 return a 12 #####选择排序 13 def rank(a): 14 for i in range(len(a)-1): 15 flag=i 16 for j in range(i+1,len(a)): 17 if a[flag]>a[j]: 18 flag=j 19 if flag!=i: 20 exch(a,i,flag) 21 return a 22 ###########插入排序 23 def rank(a): 24 for i in range(1,len(a)): 25 j=i 26 while j>0 and a[j]<a[j-1]: 27 exch(a,j,j-1) 28 j-=1 29 return a 30 31 #######归并排序 32 def rank(a): 33 rankhelper(a,0,len(a)-1) 34 def rankhelper(a,lo,hi): 35 if hi<=lo: 36 return 37 mid=int((hi-lo)/2+lo) 38 rankhelper(a,lo,mid) 39 rankhelper(a, mid + 1,hi) 40 merg(a,lo,mid,hi) 41 def merg(a,lo,mid,hi): 42 43 i=lo 44 j=mid+1 45 result=np.ones(len(a),dtype=int) ####建空数组会降低排序效率，待改进 46 result[lo:hi+1]=a[lo:hi+1] 47 48 for k in range(lo,hi+1): 49 if i>mid: 50 a[k]=result[j] 51 j+=1 52 elif j>hi: 53 a[k]=result[i] 54 i+=1 55 elif result[i]<result[j]: 56 a[k]=result[i] 57 i+=1 58 else: 59 a[k]=result[j] 60 j+=1 61 62 ####快排 63 def rank(a): 64 random.shuffle(a) 65 rankhelper(a,0,len(a)-1) 66 def rankhelper(a,lo,hi): 67 if lo>=hi: 68 return 69 j=partition(a,lo,hi) 70 rankhelper(a,lo,j-1) 71 rankhelper(a,j+1,hi) 72 def partition(a,lo,hi): 73 l1=lo+1 74 l2=hi 75 while True: 76 while a[l1]<a[lo]: 77 if l1==hi: 78 break 79 l1+=1 80 while a[l2]>a[lo]: 81 if l2==lo: 82 break 83 l2-=1 84 if l1>=l2: 85 break 86 exch(a,l1,l2) 87 exch(a,lo,l2) 88 return l2 89 90 #############堆排序 95 def sink(a,k,l): #####最小堆 96 while 2*k+1<=l: 97 j=2*k+1 98 if j<l and a[j]>a[j+1]: 99 j=j+1 100 if a[j]>a[k]: 101 break 102 exch(a,j,k) 103 k=j 104 def sink1(a,k,l): ###最大堆 105 while 2*k+1<=l: 106 j=2*k+1 107 if j<l and a[j]<a[j+1]: 108 j+=1 109 if a[j]<a[k]: 110 break 111 exch(a,j,k) 112 k=j 113 def rank(a): 114 l=len(a)-1 115 t=int(l/2)+1 116 while t>=0: 117 sink(a,t,l) 118 t-=1 119 while l>0: 120 exch(a,l,0) 121 l-=1 122 sink(a,0,l)
字符串排序 高位优先及低位优先。其中字符串排序可以和以上排序算法结合，比如和快排
1 '''def rank(s): #########低位优先 2 n=len(s) ###字符串数量 3 l=len(s[0])-1 ###长度 4 temp=[0]*len(s) ###临时数组 5 while l>=0: 6 count=[0]*257 ###计数数组 7 for i in s: 8 count[ord(i[l])+1]+=1 ###每个字符计数 9 for j in range(256): 10 count[j+1]+=count[j] 11 for k in range(n): 12 temp[count[ord(s[k][l])]]=s[k] ####将原数组按顺序呢放入到新数组中 13 count[ord(s[k][l])]+=1 #####顺序后移1 14 for t in range(n): 15 s[t]=temp[t] 16 l-=1''' 17 18 ############高位优先排序 19 def rank(s): 20 rankhelper(s,0,len(s)-1,0) 21 22 def rankhelper(s,lo,hi,d): ####引入count[1]即为长度为d的字符串数量，如果字符串长度相同，下一轮迭代count[0]==count[1]将不再递归下去 23 count=[0]*258 24 temp=[0]*len(s) 25 if lo>=hi: 26 return 27 for i in range(lo,hi+1): 28 count[chartAt(s[i],d)+2]+=1 29 for j in range(257): 30 count[j+1]+=count[j] 31 for k in range(lo,hi+1): 32 temp[count[chartAt(s[k],d)+1]]=s[k] 33 count[chartAt(s[k], d) + 1]+=1 34 for l in range(lo,hi+1): 35 s[l]=temp[l-lo] 36 for r in range(256): 37 rankhelper(s,lo+count[r],lo+count[r+1]-1,d+1) 38 39 40 def chartAt(s,d): 41 if d<len(s): 42 return ord(s[d]) 43 else: 44 return -1 45 46 s1='qwertyuiopasdfghjklzxcvbnm1234567890' 47 s=[] 48 for i in range(10): 49 #s.append(''.join(random.sample(s1,6))) ###低位优先生成长度一致的字符 50 s.append(''.join(random.sample(s1,int(random.randint(2,8))))) ###高位优先自动生成字符串 51 print(s) 52 rank(s) 53 print(s)
之后就是封装好的函数sorted使用了 python3 取消了cmp，感觉不是很灵活，自定义函数有点麻烦 python3 3个参数，list（可迭代对象）key 函数定义，按值或按键，reverse 升序或降序
1 import random 2 3 ###s生成随机字典 4 keys=[] 5 for i in range(10): 6 keys.append(random.randint(1,100)) 7 values=[] 8 s1='qwertyuiopasdfghjklzxcvbnm1234567890' 9 for j in range(10): 10 values.append(''.join(random.sample(s1,int(random.randint(2,5))))) 11 12 list1={key:value for key,value in zip(keys,values)} 13 14 print(list1) 15 ####排序主体 16 t1=sorted(list1) ###对键排序 17 t2=sorted(list1.values()) ##对值排序 18 t3=sorted(list1.items(),key=lambda x:x[0]) ###按键排序并返回字典 19 t4=sorted(list1.items(),key=lambda x:x[1]) ###按值排序并返回字典 20 print(t1) 21 print(t2) 22 print(t3) 23 print(t4)