788.cpp

// bruteForce.cpp
class Solution {
  bool valid(int number) {
    bool valid = false;
    while (number) {
      switch (number % 10) {
      case 2:
      case 5:
      case 6:
      case 9:
        valid = true;
        break;
      case 3:
      case 4:
      case 7:
        return false;
      }
      number /= 10;
    }
    return valid;
  }

public:
  int rotatedDigits(int N) {
    int count = 0;
    for (int i = 1; i <= N; ++i)
      if (valid(i))
        ++count;
    return count;
  }
};