def pr214():
def phi(n):
if isPrimeMR(n):
return n - 1
ret = n
for x in primes:
if x << 1 > n:
break
if n % x == 0:
ret = ret // x * (x - 1)
return ret
def getChainLen(n):
if d[n]:
return d[n]
t = getChainLen(phi(n)) + 1
d[n] = t
return t
primes = getPrimes(40000000)
d = [0] * 40000000
d[0] = 1
d[1] = 1
ret = 0
pbar = PBar(40000000).start()
for x in primes:
pbar.update(x)
if getChainLen(x) == 25:
ret += x
pbar.finish()
return ret
def pr071():
base = Fraction(3, 7)
ret = Fraction(0, 1)
pbar = PBar(int(1e6)+1).start()
for d in xrange(3, int(1e6) + 1):
pbar.update(d)
n = int(3.0/7*d)
t1 = Fraction(n, d)
if (t1 < base) and (t1 > ret):
ret = t1
pbar.finish()
return ret.numerator
def pr357(n):
ret = 3
primes = set(getPrimes(2*n))
pbar = PBar(n).start()
for x in xrange(3, n + 1):
if not x in primes:
pbar.update(x)
flag = True
for y in xrange(1, int(sqrt(x))+1):
if (x % y == 0):
if not (y + x / y) in primes:
flag = False
break
if flag:
ret += x
pbar.finish()
return ret
def pr336(n, s):
maxA = []
maxN = 0
cnt = 0
pbar = PBar(reduce(lambda x, y: x * y, range(1, n + 1))).start()
for p in permutations(range(n)):
cnt += 1
pbar.update(cnt)
t = rearrange(list(p[:]))
if t > maxN:
maxA = [''.join(map(lambda x: chr(ord('A')+x), p))]
maxN = t
elif t == maxN:
maxA += [''.join(map(lambda x: chr(ord('A')+x), p))]
pbar.finish()
maxA.sort()
return maxA[s-1]
