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[Java教程]Leetcode: 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.

注意两点:1. 我用的 rightshift 是>>>, 是unsigned right shift

2. & 的优先级不如 ==, 所以要把&的两个参数括起来

 1 public class Solution { 2   // you need to treat n as an unsigned value 3   public int hammingWeight(int n) { 4     int count = 0; 5     for (int i=0; i<32; i++) { 6       if ((n>>>i & 1) == 1) count++; 7     } 8     return count; 9   }10 }