Determine the Winner of a Bowling Game

This approach focuses on code clarity and reusability by creating a dedicated helper function, calculateScore. This function takes a player's pin array as input and returns their total score according to the game's rules. The main function then calls this helper for each player, compares the returned scores, and determines the winner. This modular design makes the code easy to read, test, and maintain.

1. Define a helper function calculateScore(int[] pins).
2. Inside calculateScore, initialize score = 0.
3. Loop for i from 0 to pins.length - 1: a. Determine if a bonus applies by checking the previous two turns: bonus = (i > 0 && pins[i-1] == 10) || (i > 1 && pins[i-2] == 10). b. If bonus is true, add 2 * pins[i] to score. c. Otherwise, add pins[i] to score.
4. Return the total score.
5. In the main function, call this helper to get score1 = calculateScore(player1) and score2 = calculateScore(player2).
6. Compare score1 and score2 and return 1, 2, or 0 accordingly.

The core logic is encapsulated in a calculateScore(int[] pins) method. This method initializes a score variable to 0 and iterates through the pins array from the first turn (i = 0) to the last. In each iteration i, it checks if the player scored a 10 in the previous turn (i-1) or the turn before that (i-2). Care is taken to handle the edge cases for the first two turns to avoid ArrayIndexOutOfBoundsException. If a 10 was scored in either of the two preceding turns, the current turn's value pins[i] is doubled; otherwise, it's taken as is. This value is added to the total score. After the loop, the total score is returned. The main isWinner function simply orchestrates the calls to calculateScore for both players and compares the results.

class Solution {
    public int isWinner(int[] player1, int[] player2) {
        int score1 = calculateScore(player1);
        int score2 = calculateScore(player2);
        if (score1 > score2) {
            return 1;
        } else if (score2 > score1) {
            return 2;
        } else {
            return 0;
        }
    }

    private int calculateScore(int[] pins) {
        int score = 0;
        int n = pins.length;
        for (int i = 0; i < n; i++) {
            boolean hasBonus = false;
            if (i > 0 && pins[i - 1] == 10) {
                hasBonus = true;
            }
            if (i > 1 && pins[i - 2] == 10) {
                hasBonus = true;
            }

            if (hasBonus) {
                score += 2 * pins[i];
            } else {
                score += pins[i];
            }
        }
        return score;
    }
}