#include "s0008_string_to_integer.hpp"

// 当流程很复杂的时候，画流程图: https://paste.sainnhe.dev/NQxx.png

class Automaton {
  string state = "start";
  unordered_map<string, vector<string>> table = {
      {"start", {"start", "signed", "in_number", "end"}},
      {"signed", {"end", "end", "in_number", "end"}},
      {"in_number", {"end", "end", "in_number", "end"}},
      {"end", {"end", "end", "end", "end"}}};

  int get_col(char c) {
    if (isspace(c)) return 0;
    if (c == '+' or c == '-') return 1;
    if (isdigit(c)) return 2;
    return 3;
  }

 public:
  int sign = 1;
  long long ans = 0;

  void get(char c) {
    state = table[state][get_col(c)];
    if (state == "in_number") {
      ans = ans * 10 + c - '0';
      ans = sign == 1 ? min(ans, (long long)INT_MAX)
                      : min(ans, -(long long)INT_MIN);
    } else if (state == "signed")
      sign = c == '+' ? 1 : -1;
  }
};

int Solution::myAtoi(string str) {
  Automaton automaton;
  for (char c : str) automaton.get(c);
  return automaton.sign * automaton.ans;
}