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].
Follow up:
It is very easy to come up with a solution with run time O(n*sizeof(integer)). But can you do it in linear time O(n) /possibly in a single pass?
Space complexity should be O(n).
Can you do it like a boss? Do it without using any builtin function like __builtin_popcount in c++ or in any other language
1 /** 2 * Return an array of size *returnSize. 3 * Note: The returned array must be malloced, assume caller calls free(). 4 */ 5 int* countBits(int num, int* returnSize) { 6 int *ary; 7 int i; 8 int k; 9 ary = (int *)malloc((num + 1) * sizeof(int)); 10 for(i = 0; i <= num; i++) 11 { 12 ary[i] = 0; 13 k = i; 14 while(k) 15 { 16 k &= (k-1); 17 ary[i]++; 18 } 19 } 20 *returnSize = num + 1; 21 return ary; 22 }