List all the solutions of repositories with the Forks higher than half of the watchers.
solutions refers to Solution.Id; forks higher than half of the watchers refers tto Forks>(Watchers/2);;
SELECT DISTINCT T2.Id FROM Repo AS T1 INNER JOIN Solution AS T2 ON T1.Id = T2.RepoId WHERE T1.Forks > T1.Watchers / 2