476 - Number Complement

 JAVA

• class Solution {
      public int findComplement(int num) {
          int ans = 0;
          boolean find = false;
          for (int i = 30; i >= 0; --i) {
              int b = num & (1 << i);
              if (!find && b == 0) {
                  continue;
              }
              find = true;
              if (b == 0) {
                  ans |= (1 << i);
              }
          }
          return ans;
      }
  }

C++

• class Solution {
  public:
      int findComplement(int num) {
          int ans = 0;
          bool find = false;
          for (int i = 30; i >= 0; --i) {
              int b = num & (1 << i);
              if (!find && b == 0) continue;
              find = true;
              if (b == 0) ans |= (1 << i);
          }
          return ans;
      }
  };