project euler 21-28

problem021.py

sum=[1 for i in range(10001)] 
xsum=0
for j in range(3,10001):
    i = 2
    while True:
        if j%i==0:sum[j] += (i+j/i)
        if i**2==j:sum[j] -= i
        if i**2>j:break
        i += 1
for j in range(1,10001):
    if sum[j]<10000:
        if sum[sum[j]]==j and sum[j]!=j:xsum+=j
print xsum

problem022.py

f1=None
try:
    f1 = open("names.txt","r")
    data = f1.read()
except IOError, inst:
    print inst
finally:
    if f1:f1.close()
data=data.split(',')
data.sort()
ssum=0
for j in range(len(data)):
    psum=j+1
    sum=0
    for i in range(1,len(data[j])-1):
        sum+=ord(data[j][i])-64
    psum*=sum
    ssum+=psum
print ssum

problem023.py

sum=[1 for i in range(28124)] 
for j in range(12,28124):
    i = 2
    while True:
        if i**2>j:break
        if j%i==0:sum[j] += (i+j/i)
        if i**2==j:sum[j] -= i
        i += 1
for j in range(28124):
    if sum[j]>j:sum[j]=j
    else:sum[j]=0
sum[1]=0
sum=[x for x in sum if x]
b=[i for i in range(28124)]
for i in sum:
    for j in sum:
        if i+j<28124:
            b[i+j]=0
b=[x for x in b if x]
ysum=0
for x in b:ysum+=x
print ysum

problem024.py

def pro(i):
    p=1
    for x in range(1,i+1):p*=x
    return p

a=[i for i in range(10)]
b=999999
c=range(10)
for j in range(10):
    i=0
    while True:
        if b < (i+1)*pro(9-j):
            c[j]=a[i]
            b-=(i)*pro(9-j)
            a.pop(i)
            break
        i += 1
print c

problem025.py

result = []
a, b = 1, 1
while True:
    result.append(a)
    a, b = b, a+b
    if a > 10**999:break
print len(result)+1

problem026.py

imax=0
jmax=0
x=(2**9)*(5**4)
for i in range(1,1000):
    j=1
    if x%i!=0:
        while True:
            if x*(10**j-1)%i!=0:j+=1
            else:break
    if jmax<j:
        jmax=j
        imax=i
print imax

problem027.py

a = range(1000)
a[1] = 0
for p in a:
    if not p:continue
    elif p > 31:break
    else:
        for multi in xrange(p+p, 1000, p):
            a[multi] = 0

a = [x for x in a if x]
n=0
while True:
    if n**2-79*n+1601 in a:break
    else: n+=1
y=n**2-79*n+1601
x=-79+2*n
print x*y

problem028.py

a=[2*n for n in range(1,501)]
y=1
sum=1
for x in a:
    sum+=y+x+y+2*x+y+3*x+y+4*x
    y+=4*x
print sum