LeetCode 338 Counting Bits

计算0..n每个数二进制1的个数
就用最简单的方法

class Solution {public:    vector<int> countBits(int num) {        vector<int> res;        for (int i = 0; i <= num; i++) {            int t = i;            int s = 0;            while (t) {                s += t % 2;                t /= 2;            }            res.push_back(s);        }        return res;    }};