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 weight).
For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011
, so the function should return 3.
思路比较简单,直接贴代码:
public class Solution { // you need to treat n as an unsigned value public int hammingWeight(int n) { int re = 0; int bit = 0; for(int i=0;i<32;i++) { bit = n&1; if(bit==1) re++; n>>=1; } return re; } }
当然这样写也可以:
public class Solution { // you need to treat n as an unsigned value public int hammingWeight(int n) { return Integer.bitCount(n); } }