To quote Hitler again;
"It is on the foundation of Kant's theory of knowledge that Schopenhauer built the edifice of his philosophy, and it is Schopenhauer who annihilated the pragmatism of Hegel. I carried Schopenhauer's works with me throughout the whole of the first war. from him I learned a great deal. Schopenhauer's pessimism ... has been far surpassed by Nietzsche".
[Adolf Hitler, 'Table Talk' May 1944]

This is unequivocal. Hitler's own secretary provided evidence enough for the world renowned [non-Nazi!] British historian Hugh Trevor-Roper to report that;
"We know from his secretary, that Hitler could quote Schopenhauer by the page; and the other German philosopher of will power, Nietzsche, whose work he afterwards presented to Mussolini, was also often on his lips".