From 18c066ac89eee7ea5e112c31dcc57b8e76002b06 Mon Sep 17 00:00:00 2001
From: Madhusudan.C.S
Date: Sun, 11 Oct 2009 16:51:43 +0530
Subject: Almost last set of official solutions and final quiz.

---
 day1/exercise/aliquot.py         | 19 +++++++++++++++----
 day1/exercise/amicable.py        | 29 ++++++++++++++++++-----------
 day1/exercise/even_perfect_4a.py | 14 ++++++++++++++
 day1/exercise/pytriads.py        | 13 ++++++++-----
 4 files changed, 55 insertions(+), 20 deletions(-)
 create mode 100644 day1/exercise/even_perfect_4a.py

(limited to 'day1/exercise')

diff --git a/day1/exercise/aliquot.py b/day1/exercise/aliquot.py
index f07cd77..96ea916 100644
--- a/day1/exercise/aliquot.py
+++ b/day1/exercise/aliquot.py
@@ -1,8 +1,19 @@
+def is_perfect_square(n):
+    i = 1
+    while i * i < n:
+        i += 1
+    return i * i == n, i
+
 def aliquot(n):
-    sum = 0
-    for i in range(1, (n/2)+1):
+    sum = 1
+    i = 2
+
+    is_ps, root = is_perfect_square(n)
+    while i < root:
         if n % i == 0:
-            sum += i
+            sum += i + (n / i)
+        i += 1
     return sum
 
-print aliquot(14)
+n = int(raw_input('Enter a number? '))
+print aliquot(n)
diff --git a/day1/exercise/amicable.py b/day1/exercise/amicable.py
index 0986e33..c9aea71 100644
--- a/day1/exercise/amicable.py
+++ b/day1/exercise/amicable.py
@@ -1,18 +1,25 @@
-import math
+def is_perfect_square(n):
+    i = 1
+    while i * i < n:
+        i += 1
+    return i * i == n, i
 
 def aliquot(n):
-    sum = 0
-    for i in range(1, int(math.sqrt(n))+1):
+    sum = 1
+    i = 2
+
+    is_ps, root = is_perfect_square(n)
+    while i < root:
         if n % i == 0:
-            sum += i + n/i
+            sum += i + (n / i)
+        i += 1
     return sum
 
 amicable = []
-for n in range(10000, 100000):
-    m = aliquot(n)
-    if aliquot(m) == n:
-        amicable.append((m, n))
 
-print amicable
-
-# please please please profile this.
+n = 1000
+while n < 10000:
+    m = aliquot(n)
+    if m > n and aliquot(m) == n:
+        print m, n
+    n += 1
diff --git a/day1/exercise/even_perfect_4a.py b/day1/exercise/even_perfect_4a.py
new file mode 100644
index 0000000..ccadc1c
--- /dev/null
+++ b/day1/exercise/even_perfect_4a.py
@@ -0,0 +1,14 @@
+def all_digits_even(n):
+    if n < 0: n = -n
+    while n > 0:
+        if n % 2 == 1:
+            return False
+        n /= 10
+    return True
+
+i = 46
+while i <= 94:
+    square = i * i
+    if all_digits_even(square):
+        print square
+    i += 1
diff --git a/day1/exercise/pytriads.py b/day1/exercise/pytriads.py
index 916c000..4c47313 100644
--- a/day1/exercise/pytriads.py
+++ b/day1/exercise/pytriads.py
@@ -10,9 +10,12 @@ def gcd(a, b):
     else:
         return gcd(b, a%b)
 
-for a in range(3, 100):
-    for b in range(a+1, 100):
-        ips, c = is_perfect_square((a * a) + (b * b))
-        if ips and gcd(a, b) == 1:
+a = 3
+while a < 100:
+    b = a + 1
+    while b < 100:
+        is_ps, c = is_perfect_square((a * a) + (b * b))
+        if is_ps and gcd(a, b) == 1:
             print a, b, c
-
+        b += 1
+    a += 1
-- 
cgit