【LeetCode】Number of 1 Bits

标签：leetcode

      题意：

     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：

     计算一个无符号 32 位整数的二进制表示有多少个 1. 只要每次取最后一位判断是否是 1, 然后进行右移操作就好。复杂度 O(32).

     代码：

     C++：

class Solution {
public:
    int hammingWeight(uint32_t n) {
        int ans = 0;
        for(int i = 0;i < 32;++i)
        {
            if(n & 1) ans++;
            n = n >> 1;
        }
        return ans;
    }
};

     Python：

class Solution:
    # @param n, an integer
    # @return an integer
    def hammingWeight(self, n):
        ans = 0
        for i in range(0,32):
            ans = ans + (n&1)
            n = n>>1
        return ans

【LeetCode】Number of 1 Bits

标签：leetcode

原文地址：http://blog.csdn.net/jcjc918/article/details/44489475