Bag of Tokens Python Solution with Tests

lcpy gen -n 948   # by problem number
lcpy gen -s bag_of_tokens   # by problem name

Input: tokens = [100], power = 50
Output: 0
Explanation: Since your score is 0 initially, you cannot play the token face-down. You also cannot play it face-up since your power (50) is less than tokens[0] (100).

Input: tokens = [200,100], power = 150
Output: 1
Explanation: Play token1 (100) face-up, reducing your power to 50 and increasing your score to 1.

Input: tokens = [100,200,300,400], power = 200
Output: 2
Explanation: Play the tokens in this order to get a score of 2:
Play token0 (100) face-up, reducing power to 100 and increasing score to 1.
Play token3 (400) face-down, increasing power to 500 and reducing score to 0.
Play token1 (200) face-up, reducing power to 300 and increasing score to 1.
Play token2 (300) face-up, reducing power to 0 and increasing score to 2.

class Solution:
    # Time: O(n log n)
    # Space: O(n) for the sorted copy
    def bag_of_tokens_score(self, tokens: list[int], power: int) -> int:
        tokens = sorted(tokens)
        left, right = 0, len(tokens) - 1
        score = 0
        best = 0
        while left <= right:
            if power >= tokens[left]:
                # Cheapest token face-up for score
                power -= tokens[left]
                left += 1
                score += 1
                best = max(best, score)
            elif score >= 1:
                # Most expensive token face-down for power
                power += tokens[right]
                right -= 1
                score -= 1
            else:
                break
        return best