leetcode-Counting Bits

Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1’s in their binary representation and return them as an array.

Example:
For num = 5 you should return [0,1,1,2,1,2].

计算比特位的1的个数，利用位运算来解决

	vector<int> countBits(int num) 
	{
		vector <int> ret;
		for (int i = 0; i <= num; i++)
		{



			int  x = i, count = 0;


			while (x)
			{
				if (x & 1)
				{
					count++;
				}
				x >>= 1;
			}

			ret.push_back(count);

		}

		return ret;
	}