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. Credits: Special thanks to @ syedee for adding this problem and creating all test cases.
这个完全搞不懂呢。。
参考了这位的代码
/**
* @param {number} num
* @return {number[]}
*/
var countBits = function(num) {
var ret=new Array(num + 1);
ret[0]=0;
for (var i = 1; i <= num; ++i)
ret[i] = ret[i&(i - 1)] + 1;
return ret;
};
