[Leetcode 191] Number of 1 Bits

Source: Internet
Author: User

1 topics

Write a function that takes an unsigned integer and returns the number of ' 1 ' bits it has (also known as the Hamming weigh T).

For example, the 32-bit integer ' One ' 00000000000000000000000000001011 has a binary representation, so the function should return 3.

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

2 analysis

Start thinking is to convert to bit array again a check whether it is 1, later found the Java system function Bitcount, found to meet the conditions.

Another way I look at others is by looping 32 times, each time with 1 and moving one bit to the right. The idea is fine.

3 Code

 public  int  hammingweight (int   N) { return   Integer.bitcount (n); }
       Public int hammingweight (int  n) {            int sum=0;              for (int i=0;i<32;i++) {                sum+=n&1;               n= n>>1;            }             return sum;        }

[Leetcode 191] Number of 1 Bits

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