[Leetcode] Number of 1 bits about bit operation

Number of 1 Bits

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.

The solution to the problem is still very clear.

One, the whole number does not change, the mask shifts right

Use a mast constant with this number to operate and get the corresponding bit whether it is zero

int mask = 1;

int num;

int count = 0;

For shift=0:31

Mask = Mask << shift

int bit = num & mask;

If bit!=0

count++;

End

End

Second, mask unchanged, Integer right Shift method.

This is only suitable for non-negative integers, negative numbers to the right, sign bits will be copied, and eventually become all one.

[Leetcode] Number of 1 bits about bit operation