Which film won the Academy Award for Best Picture for 1949?

Which film won the Academy Award for Best Picture for 1947? Who directed 'Gentleman's Agreement', the Best Picture winner for 1947? Which film won the Academy Award for Best Picture for 1948? Who directed 'Hamlet', the Best Picture winner for 1948? Who directed 'All the King's Men', the Best Picture winner for 1949? Which film won the Academy Award for Best Picture for 1950? Which film won the Academy Award for Best Picture for 1951? Who directed 'An American in Paris', the Best Picture winner for 1951?