Bag of Tokens LeetCode solution in Java

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class Solution {
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  public int bagOfTokensScore(int[] tokens, int power) {
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    // initially score is 0, that's why in these conditions, return 0.
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    if (tokens.length == 0 || power < tokens[0]) return 0;
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    Arrays.sort(tokens); // sort the array
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    int i = 0;
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    int r = tokens.length - 1;
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    int score = 0;
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    int answer = 0;
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    while (i <= r) {
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      if (power >= tokens[i]) {
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        power -= tokens[i++];
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        answer = Math.max(answer, ++score); // play all tokens, but store the max score in answer.
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      } else if (score > 0) {
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        power += tokens[r--]; // take power from greatest element
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        score--; // decrease by 1.
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      }
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      // when you can't do any of the steps (face up, face down)
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      else return answer;
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    }
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    return answer;
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  }
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}