Algorithm optimization on arrays

Question

I am writing an algorithm that should return "yes" if a list of customers are to pay for a movie and receive their change (money) considering the the clerk starts receiving payments with an empty cashier pause, meaning he cant give change from the start. The movie costs 25 $ so if a customer has 50 $ the clerk has to refuse unless he has already received 25 $ from previous customer so is able to use that as change for the next customer.

I have such algorithm

public static String Tickets(int[] peopleInLine) {
 int sumOfMoneyWithCashier = 0;
 int cost = 25;
 for (int i = 0; i < peopleInLine.length; i++) {
 if (peopleInLine[i] == cost) {
 sumOfMoneyWithCashier += peopleInLine[i];
 if (peopleInLine[i + 1] == cost) {
 sumOfMoneyWithCashier += cost;
 } else if (peopleInLine[i + 1] > cost) {
 int change = peopleInLine[i + 1] - cost;
 if (sumOfMoneyWithCashier >= change) {
 sumOfMoneyWithCashier -= change;
 } else {
 System.out.println("no");
 return "NO";
 }
 }
 } else if (peopleInLine[i] > cost) {
 int change = peopleInLine[i] - cost;
 if (sumOfMoneyWithCashier >= change) {
 sumOfMoneyWithCashier -= change;
 } else {
 System.out.println("no");
 return "NO";
 }
 }
 }
 System.out.println("YES");
 return "YES";
}

Now it works but not perfect , how can i improve this code so it check handles most of the scenario, ignore case where customer comes with less than 25. customers must come with multiples of 25 between range of {25, 50, 100} How can i make this code better is the question , i would appreciate an example code and explanation basically

Line.Tickets(new int[] {25, 25, 50}) // => YES 
Line.Tickets(new int[]{25, 100}) // => NO. Vasya will not have enough money to give change to 100 dollars
Line.Tickets(new int[] {25, 25, 50, 50, 100}) // => NO. Vasya will not have the right bills to give 75 dollars of change (you can't make two bills of 25 from one of 50)

• Joakim Danielson: How can I improve/make it better is a pretty vague question. If you have a specific situation when the program misbehaves or gives the wrong result than explain that situation (or situations) with example of given input and the result vs the expected result.
• valik: ok i got the task out of a codewars.com so there 12 tests it should pass , currently it passes 10 test , the problem is that codewars,com doesnt show you the tests inputs that were used @JoakimDanielson
• valik: (peopleInLine[i + 1] == cost) i am doing this to represent next element in the array @SamzSakerz
• valik: its just my way of getting next value in an array @SamzSakerz
• valik: may be not the best way @SamzSakerz

Answer 1

This is a simple solution to what you are trying to do see if it works out for you :)

public static String Tickets(int[] peopleInLine) {
 int d25 = 0, d50 = 0;
 for (int aPeopleInLine : peopleInLine) {
 if (aPeopleInLine == 25){
 d25++;
 }
 if (aPeopleInLine == 50) {
 d25--;
 d50++;
 }
 if (aPeopleInLine == 100) {
 if (d50 > 0) {
 d50--;
 d25--;
 } else {
 d25 -= 3;
 }
 }
 if (d25 < 0){
 return "NO";
 }
 }
 return "YES";
}

• valik: yes it works perfectly for all cases , can you tell me the things wrong with code logic ? @SamzSakerz