标签：python
问题描述：
A permutation is an ordered arrangement of objects. For example, 3124 is one possible permutation of the digits 1, 2, 3 and 4. If all of the permutations are listed numerically or alphabetically, we call it lexicographic order. The lexicographic permutations of 0, 1 and 2 are:
012 021 102 120 201 210
What is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9?
翻译：
一个排列就是物体按一定的顺序摆放。例如，3124是数字1, 2, 3, 4的一种排列。如果所有排列都按照数字顺序或字母顺序排列的话，我们就称之为词法顺列。0, 1, 2的所有词法排列是：
012 021 102 120 201 210
0, 1, 2, 3, 4, 5, 6, 7, 8, 9的第100万个词法排列是……？
其实就是求全排列之后的第几个数的问题，可以转化成树的模型来做
num,s=[0,1,2,3,4,5,6,7,8,9],1
for i in range(1,11):
s*=i
resu,length=[0]*10,0
pos=1000000
def updataNum(n):
for i in range(n+1,10):
num[i-1]=num[i]
def f(sum,per,n):
global length
if 10-length==1:
return
size = n/per
if n%per==0:
size-=1
resu[length] = num[size]
updataNum(size)
n = n-(size)*per
sum /= (10-length)
per = sum/(10-length-1)
length+=1
f(sum, per , n)
f(s, s/10, pos)
resu[length]=num[0]
print resu
projecteuler---->problem=24----Lexicographic permutations,布布扣,bubuko.com
projecteuler---->problem=24----Lexicographic permutations
标签：python
原文地址：http://blog.csdn.net/q745401990/article/details/29591289
