def test_solution_3():
sol = Solution()
x = [7, 6, 4, 3, 1]
result = sol.max_profit(x)
assert result == 0
def test_solution_1():
sol = Solution()
x = [7, 1, 5, 3, 6, 4]
result = sol.max_profit(x)
assert result == 7
def test_solution_2():
sol = Solution()
x = [1, 2, 3, 4, 5]
result = sol.max_profit(x)
assert result == 4
