leetcode之Number of 1 Bit

Write a function that takes an unsigned integer and returns the number of ’1’ bits it has (also known as the Hamming weight).

For example, the 32-bit integer ’11’ has binary representation 00000000000000000000000000001011, so the function should return 3.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

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  public int hammingWeight(int n) {
        int i=0;
        while(n!=0){
            n=n&n-1;
            i++;
        }
        return i;
    }

一遍就過了。炒雞的自信。。因爲在《編程之美》上看到過。但是一直不知道 怎麼去解釋這個算法 。今天和女朋友討論了一下。其實就是每次減1的時候。把一個1變成0，而且只變一個1.