1. 实现 f(x) = 2 * f(x -1) + x * x：
def f(x):
if x == 0:
return x
else:
return f(x-1) * 2 + x * x
for x in xrange(1,10):
print f(x)
2. 一个简单类的实现
class tClass():
def __init__(self,orig=0):
self.storedValue = orig
def read(self):
return self.storedValue
def write(self,x):
self.storedValue = x
def Test():
a = tClass()
print "a: " + str(a.read())
a.write(10)
print "a: " + str(a.read())
b = tClass(100)
print "b: " + str(b.read ())
if __name__ == '__main__':
Test()
运行结果：
3. 地精排序：
import random
def gnome_sort(seq):
i = 0
while i < len(seq):
if i == 0 or seq[i-1] <= seq[i]:
i += 1
else:
seq[i], seq[i-1] = seq[i-1],seq[i]
i -= 1
#seq = range(1,11)
#print seq
#i = 0
#while(i < 10):
# seq[i] = random.randint(1,10)
# i += 1
#print seq
#gnome_sort(seq)
#print seq
#-----------------------------
#-----------------------------
i = 0
seq = []
while i < 10:
seq.append(random.randint(1,100))
i += 1
print "Origin: ",seq
gnome_sort(seq)
#seq.sort()
print "After sort:",seq
运行结果：
4. 冒泡排序：
import random
def bubblesort(a):
for i in xrange(0,len(a)):
for j in xrange(i,len(a)):
if a[j] < a[i]:
a[j],a[i] = a[i],a[j]
def Test():
a = []
for i in xrange(1,10):
a.append(random.randint(1,100))
print "orginal: ",a
#print "after sort: "
bubblesort(a)
print "after sort:",a
if __name__ == '__main__':
Test()
运行结果：
5. 直接插入排序
# -*- coding: utf-8 -*-
import random,time
r = random.Random()
li = [r.randint(1,300) for i in xrange(20)] #生成随机数
print li
print "-"*30
starttime = time.time()
for i in range(len(li)):
temp = li[i]
j = i
while j > 0 and temp < li[j-1]:
li[j] = li[j-1]
j -= 1
li[j] = temp
print li
endtime = time.time()
print endtime - starttime
运行结果：
6.快速排序
import random
def sort(L):
if not L: return []
else:
return sort([x for x in L[1:] if x < L[0]]) + L[0:1] + sort([x for x in L[1:] if x >= L[0]])
L = [ random.randint(1,100) for i in xrange(10)]
print L
LL = sort(L)
print "After sort: "
print LL
运行结果：
7. 最大子序列和
def maxSum(a):
currSum = 0
mSum = 0
for i in a:
currSum += i
if currSum > mSum :
mSum = currSum
elif currSum < 0:
currSum = 0
return mSum
def maxSum_1(a): #第二种实现方式
currSum = 0
mSum = 0
for i in xrange(0,len(a)):
for j in xrange(i,len(a)):
currSum = 0
for k in a[i:j]:
currSum += k
if currSum > mSum:
mSum = currSum
return mSum
def Test():
t = [-2, 11, -4, 13, -5, -2]
print "maxSum: ", maxSum(t)
print "maxSum_1: ", maxSum_1(t)
if __name__ == '__main__':
Test()
运行结果：
