Integer Replacement LeetCode solution in Java

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class Solution {
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  public int integerReplacement(int n) {
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    return (int) calc(n, 0);
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  }
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  public long calc(long n, int i) {
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    if (n == 1) return i;
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    if (n < 1) return 0;
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    long a = Long.MAX_VALUE, b = Long.MAX_VALUE, c = Long.MAX_VALUE;
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    if (n % 2 == 0) a = calc(n / 2, i + 1);
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    else {
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      b = calc(n - 1, i + 1);
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      c = calc(n + 1, i + 1);
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    }
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    long d = Math.min(a, Math.min(b, c));
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    return d;
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  }
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}