Implement a java code for computing f$($x$),$ where the complexity of your code should be O$($n$).$ You should explain how your program is working.$(4$pts$)$

f$($x$)=$ a$\_$nx$^$n $+$ a$\_($n $-1)$x$*($n $-1)+$ a$\_($n $-2)$x$^($n $-2)+...+$ a$\_1$x$^1+$ a$\_0$