欧拉项目python代码(12--)

第12题：

拥有超过500个因数的第一个三角数（1+2+3+4+......)

def findivisionnum(num):
    count = 0
    n=1
    import math
    while count<num:
        count = 0
        for i in range(1,int(math.sqrt(triangle(n)))+1):
            if not triangle(n)%i:
                count +=2
        if int(math.sqrt(triangle(n)))==math.sqrt(triangle(n)):
                count -=1
        n += 1 
    return triangle(n-1)

def triangle(n):
  return n*(n+1)/2

print findivisionnum(500)

[Finished in 13.9s]

第14题：

def findlength(n):
    count = 0
    while n!=1:
        if not n%2:
            n /=2
            count +=1
        else:
            n =3*n+1
            count +1
    countcopy=count
    count=0
    return countcopy


def lengthmax(num):
    i=1
    max_count=1
    max_number=0
    while i<=num:
        if max_count<findlength(i):
            max_count=findlength(i)
            max_number=i
            i +=1
        else:
            i +=1
    return max_number


print lengthmax(1000000)

第15题：

def findsum1(num1):
    root=1
    for i in range(1,2*num+1):
        root *= i
    for i in range(1,num+1):
        root /= i
        root /= i
    return root

print findrout(20)