选择算法

[leo@hadoop ~]$ cat loop2.py
a=[12,324,3423,42,234,756,3214,64,13,234]
alen=len(a)
print "original a is:",a
for x in range(alen):
  b=a[x-alen:]
  #print "x is ",x,"b is:",b
  for j,va in enumerate(b):
     #print "b len",len(b),"j is",j
    if j<len(b)-1:
      if b[0]<b[j+1]:
        k=b[0]
        b[0]=b[j+1]
        b[j+1]=k
  a[x-alen:]=b[:]
 # print "x is ",x,"a is:",a
print "final a is:", a
[leo@hadoop ~]$ python loop2.py
original a is: [12, 324, 3423, 42, 234, 756, 3214, 64, 13, 234]
final a is: [3423, 3214, 756, 324, 234, 234, 64, 42, 13, 12]