Add more solutions

Added solutions for problems 21, 22, 23, 24 and 25 both in C and
in python

Python/p018.py

@@ -28,12 +28,12 @@ def main():
 
     for line in fp:
         triang.append(line.strip('\n').split())
-    
+
     fp.close()
 
     for i in range(len(triang)):
         triang[i] = list(map(int, triang[i]))
-   
+
     max_ = 0
     sum_triangle(triang, 15, 0, 0, 0)
 

Python/p021.py

@@ -0,0 +1,40 @@
+#!/usr/bin/python3
+
+import math
+
+from timeit import default_timer
+
+def sum_of_divisors(n):
+    limit = math.floor(math.sqrt(n)) + 1
+
+    sum_ = 1
+
+    for i in range(2, limit):
+        if n % i == 0:
+            sum_ = sum_ + i
+            if n != i * i:
+                sum_ = sum_ + n // i
+
+    return sum_
+
+def main():
+    start = default_timer()
+
+    sum_ = 0
+
+    for i in range(2, 10000):
+        n = sum_of_divisors(i)
+        if i != n and sum_of_divisors(n) == i:
+            sum_ = sum_ + i + n
+
+    sum_ = sum_ // 2
+
+    end = default_timer()
+
+    print('Project Euler, Problem 21')
+    print('Answer: {}'.format(sum_))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()

Python/p022.py

@@ -0,0 +1,35 @@
+#!/usr/bin/python3
+
+from timeit import default_timer
+
+def main():
+    start = default_timer()
+
+    try:
+        fp = open('names.txt', 'r')
+    except:
+        print('Error while opening file {}'.format('names.txt'))
+        exit(1)
+
+    names = list(fp.readline().replace('"', '').split(','))
+    names.sort()
+
+    sum_ = 0
+
+    for i in range(len(names)):
+        l = len(names[i])
+        score = 0
+        for j in range(l):
+            score = score + ord(names[i][j]) - ord('A') + 1
+        score = score * (i + 1)
+        sum_ = sum_ + score
+
+    end = default_timer()
+
+    print('Project Euler, Problem 22')
+    print('Answer: {}'.format(sum_))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()

Python/p023.py

@@ -0,0 +1,51 @@
+#!/usr/bin/python3
+
+import math
+
+from timeit import default_timer
+
+def is_abundant(n):
+    limit = math.floor(math.sqrt(n)) + 1
+    sum_ = 1
+
+    for i in range(2, limit):
+        if n % i == 0:
+            sum_ = sum_ + i
+            if n != i * i:
+                sum_ = sum_ + n // i
+
+    return sum_ > n
+
+def main():
+    start = default_timer()
+
+    ab_nums = [False] * 28124
+
+    for i in range(12, 28124):
+        ab_nums[i] = is_abundant(i)
+
+    sums = [False] * 28124
+
+    for i in range(1, 28123):
+        if ab_nums[i]:
+            for j in range(i, 28123):
+                if ab_nums[j]:
+                    sum_ = i + j
+                    if sum_ <= 28123:
+                        sums[sum_] = True
+
+    sum_ = 0
+
+    for i in range(1, 28124):
+        if not sums[i]:
+            sum_ = sum_ + i
+
+    end = default_timer()
+
+    print('Project Euler, Problem 23')
+    print('Answer: {}'.format(sum_))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()

Python/p024.py

@@ -0,0 +1,21 @@
+#!/usr/bin/python3
+
+from itertools import permutations
+
+from timeit import default_timer
+
+def main():
+    start = default_timer()
+
+    perm = list(permutations('0123456789'))
+    res = int(''.join(map(str, perm[999999])))
+
+    end = default_timer()
+
+    print('Project Euler, Problem 24')
+    print('Answer: {}'.format(res))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()

Python/p025.py

@@ -0,0 +1,28 @@
+#!/usr/bin/python3
+
+from timeit import default_timer
+
+def main():
+    start = default_timer()
+
+    fib1 = 1
+    fib2 = 1
+    fibn = fib1 + fib2
+
+    i = 3
+
+    while len(str(fibn)) < 1000:
+        fib1 = fib2
+        fib2 = fibn
+        fibn = fib1 + fib2
+        i = i + 1
+
+    end = default_timer()
+
+    print('Project Euler, Problem 25')
+    print('Answer: {}'.format(i))
+
+    print('Elapsed time: {:.9f} seconds'.format(end - start))
+
+if __name__ == '__main__':
+    main()