Google – Hamming Distance of Two Binary Code

Google – Hamming Distance of Two Binary Code
求a和b的hamming distance, a和b都小于2^64.
[Solution]
hamming distance就是两个integer的binary representation有多少个bit不同。
直接xor算1的个数就好了。
如果内存小于2^64（约等于7G），那就分段来比。
但是Reference里提供的面经里有说存字典，想了好久也没想明白怎么存字典…

  public int hammingDistance(long a, long b) {

    long x = a ^ b;

    int result = 0;

    for (int i = 0; i < 64; i++) {

      result += (x & 1);

      x >>= 1;

    }

 

    return result;

  }

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