LockerPuzzle.java; Professor Estrada HW

LockerPuzzle.java

package com.saurishsrivastava;
/* name: Saurish Srivastava; locker puzzle, will determine whether or not the locker is opened after a series of students opening it: 10 PM on 24 March 2020 */

public class LockerPuzzle {
    /**
     * Main method
     */
    public static void main(String[] args) {
        /* create the Locker array */
        boolean[] lockers  = new boolean[101]; // create a locker array of 101 booleans (we will get rid of the 0th boolean)

        /* First we need to close all the lockers */
        lockersClosed(lockers);

        /* Next we need to run all of the student trials */
        studentsTrial(lockers);

        /* Lastly we need to print out the open lockers */
        printFunction(lockers);
    }

    public static boolean isOpen(boolean i) {
        return i; // if the boolean is true (open) it will return true, if not, it will return false (closed)
    }

    /* Close all the lockers in the array */
    public static void lockersClosed(boolean[] lockers) {
        for(int x = 0; x < lockers.length; x++) {
            lockers[x] = false; // could also be achieved with the ArrayFill method
        }
    }

    /* Run the students closing the lockers in their patterns */
    public static void studentsTrial(boolean[] lockers) {
        for (int y = 1; y <= (lockers.length); y++) { // the first for loop counts how many people have gone
            for(int z = 0; z < lockers.length; z+=y) { // z+y because fourth person will go every FOURTH locker etc
                if (isOpen(lockers[z])) {
                    lockers[z] = false; // set the locker to false if it is currently true
                } else {
                    lockers[z] = true; // set the locker to true if it is currently false
                }
            }
        }
    }

    public static void printFunction(boolean[] lockers) {
        for (int z = 1; z < lockers.length; z++) { // only take from z=1 because we don't include locker 0.
            if (isOpen(lockers[z])) {
                System.out.print("L" + (z) + " "); // use print not println so it can work numerous times and be in one line; z+1 bc we start at 0 but there is no locker number 0
            } // no need for else statement bc we don't need to do anything to the lockers that are closed
        }
    }
}