Solve problem 179.

python/e179.py

@@ -0,0 +1,33 @@
+from lib_prime import get_divisors_count
+
+
+def euler_179_orig():
+    r = 0
+    for n in range(2, 10**7):
+        if n % 10**5 == 0:
+            print(n)
+        if get_divisors_count(n) == get_divisors_count(n + 1):
+            r += 1
+    return r
+
+
+def euler_179():
+    """ Much faster version. """
+    upper = 10**7
+    ndivs = [1 for _ in range(0, upper + 2)]
+    for d in range(2, upper // 2):
+        for i in range(d, upper + 2, d):
+            ndivs[i] += 1
+
+    r = 0
+    for i in range(2, upper + 1):
+        if ndivs[i] == ndivs[i + 1]:
+            r += 1
+    return r
+
+
+if __name__ == "__main__":
+    solution = euler_179()
+    print("e179.py: " + str(solution))
+    assert(solution == 986262)
+