Tower of Hanoi (Hanoi)

Algorithm Analysis:

If there are three plates on tower A, need to move to Tower C, according to certain rules, the need for the use of Tower B, the case of movement is as follows:

When there are 3 plates, a total of 2^3-1 steps are required, and when there are n plates, a 2^n-1 step is required.

Algorithm implementation:

<span style= "Font-family:microsoft yahei;font-size:18px;" ><? PHP
//Hanoi Tower implements
//n plates, x, Y, Z, three pillars.
 function Hanoi ($n, $x, $y, $z) {
        if ($n = = 1) {
               echo ' move 1 from '. $x. "To" $z. " </br> ";
        } else{
               Hanoi ($n-1, $x, $z, $y);//The n-1 plate is moved from x through Y to the z
            echo "move". $n. "From" $x. "to" $z. " </br> ";
            Hanoi ($n-1, $y, $z, $x);//N-1 a plate by x from Y to Z
        }
 }
 Hanoi (3, ' x ', ' y ', ' z ');</span>