https://leetcode.com/problems/counting-bits/

1. Use % to calculate bits:

  1. //8 ms    8.6 MB
  3. class Solution {
  4. public:
  5.     vector<int> countBits(int num) {
  6.         vector<int> result;
  8.         for(int i = 0; i <= num; i++) {
  9.             result.push_back(HowManyBits(i));
  10.         }
  12.         return result;
  13.     }
  14. private:
  15.     int HowManyBits(int i){
  16.         int count = 0;
  17.         while(i > 1){
  18.             count += (i % 2);
  19.             i = i / 2;
  20.         }
  21.         return count + i;
  22.     }
  23. };