[Hacker Rank]: Project Euler #1: Multiples of 3 and 5 solved ✓. Cover…

src/lib/exercises/src/hackerrank/projecteuler/euler001.cpp

@@ -43,7 +43,12 @@ unsigned long euler001(int a, int b, int n) {
   // Since, we need the sum of multiples less than N
   n = n - 1;
 
-  unsigned long lcm = (a * b) / gcd(a, b);
+  unsigned long the_gcd = gcd(a, b);
+  if (the_gcd == 0) {
+    return 0;
+  }
+
+  unsigned long lcm = (a * b) / the_gcd;
 
   return sum_of_arithmetic_progression(n, a) +
          sum_of_arithmetic_progression(n, b) -

src/tests/unit/lib/hackerrank/projecteuler/euler001.testcases.json

@@ -1,6 +1,32 @@
 [
-  { "a": 3, "b": 5, "n": 10, "expected": 23 },
-  { "a": 5, "b": 3, "n": 10, "expected": 23 },
-  { "a": 3, "b": 5, "n": 100, "expected": 2318 },
-  { "a": 3, "b": 5, "n": 1000, "expected": 233168 }
+  {
+    "a": 0,
+    "b": 0,
+    "n": 0,
+    "expected": 0
+  },
+  {
+    "a": 3,
+    "b": 5,
+    "n": 10,
+    "expected": 23
+  },
+  {
+    "a": 5,
+    "b": 3,
+    "n": 10,
+    "expected": 23
+  },
+  {
+    "a": 3,
+    "b": 5,
+    "n": 100,
+    "expected": 2318
+  },
+  {
+    "a": 3,
+    "b": 5,
+    "n": 1000,
+    "expected": 233168
+  }
 ]