3 different functions to check if a number is prime

Author: duke-mai

check_prime.py

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+# Author:   Tan Duc Mai
+# Email:    [email protected]
+
+"""
+Three different functions to check whether a given number is a prime.
+Return True if it is a prime, False otherwise.
+Those three functions, from a to c, decreases in efficiency (takes longer time).
+"""
+
+
+def is_prime_a(n):
+    from math import sqrt
+    if n < 2:
+        return False
+    sqrt_n = int(sqrt(n))
+    for i in range(2, sqrt_n + 1):
+        if n % i == 0:
+            return False
+    return True
+
+
+def is_prime_b(n):
+    if n > 1:
+        if n == 2:
+            return True
+        else:
+            for i in range(2, n):
+                if n % i == 0:
+                    return False
+            return True
+    return False
+
+
+def is_prime_c(n):
+    divisible = 0
+    for i in range(1, n + 1):
+        if n % i == 0:
+            divisible += 1
+    if divisible == 2:
+        return True
+    return False