bulls-and-cows.cc

// Bulls and Cows
class Solution {
public:
  string getHint(string secret, string guess) {
    int c[10] = {}, a = 0, b = 0;
    for (int i = 0; i < secret.size(); i++) {
      if (secret[i] == guess[i])
        a++;
      else {
        if (c[secret[i]-'0']++ < 0) b++;
        if (c[guess[i]-'0']-- > 0) b++;
      }
    }
    return to_string(a)+"A"+to_string(b)+"B";
  }
};