std::vector getOptimalStrategy()

in simple_game/comm.h [188:233]

• 35 lines of code
• 10 McCabe index (conditional complexity)

   std::vector<float> getOptimalStrategy(const std::string &key) const override { 
     if (key == "s" || key.substr(0, 5) == "done-") return {};

     // Skip "P1-r" or "P2-r"; 
     int i = 4;
     std::vector<int> actions;
     while (i < (int)key.size()) {
       if (key[i] == '-') break; 
       else {
         actions.push_back(key[i] - '0');
         i ++;
       } 
     }

     if (i == (int)key.size()) {
       // Player 2
       assert((int)actions.size() == commOptions_.numRound);
       int n = 0;
       for (int i = commOptions_.numRound - 1; i >= 0; --i) {
         // Little Endian
         n = ((n << 1) | actions[i]);
       }
       std::vector<float> policy(commOptions_.possibleCards, 0.0f);

       if (n < (int)policy.size()) {
         policy[n] = 1.0;
       } else {
         // Reachability should be zero here. 
         // But since the policy of any infoSet is requested, we need to return something here.
         std::fill(policy.begin(), policy.end(), 1.0f / commOptions_.possibleCards);
       }
       return policy;
     } else {
       // Player 1. Binary encoding.
       int n = std::stoi(key.substr(i + 1, -1));
       std::vector<int> action_seq;
       for (int k = 0; k < commOptions_.numRound; ++k) {
         // Little Endian. 8 = 1000 => Action sequence [0, 0, 0, 1].
         action_seq.push_back(n % 2);
         n /= 2;
       }

       if (action_seq[actions.size()] == 0) return {1.0, 0.0};
       else return {0.0, 1.0};
     }
   }