add tests for task1

1. problem_rl/solution.cpp

@@ -0,0 +1,46 @@
+#include <iostream>
+#include <assert.h>
+
+#define ull unsigned long long
+#define ll long long
+
+ull gcd_cycle(ll x, ll y);
+ull gcd_recursive(ull x, ull y);
+
+int main() {
+  ull x = 0, y = 0, g;
+  int res;
+  
+  res = scanf("%llu %llu", &x, &y);
+  assert(res == 2);
+  g = gcd_cycle(x, y);
+  printf("%llu\n", g);
+  return 0;
+}
+
+ull gcd_recursive(ull x, ull y) {
+  ull q;
+  if (y > x)
+    return gcd_recursive(y, x);
+  assert (y > 0);
+  q = x % y;
+  if (q == 0)
+    return y;
+  return gcd_recursive(y, q);
+}
+
+ull gcd_cycle(ll x, ll y) {
+  x = llabs(x);
+  y = llabs(y);
+
+  if (x == 0) return y;
+  if (y == 0) return x;
+
+  while (y != 0) {
+    ll r = x % y;
+    x = y;
+    y = r;
+  }
+
+  return x;
+}