C++ Pos::isValid方法代码示例

int solve(){
  memset(tick, 0x1f, sizeof(tick));  
  Pos start = findCh('S');
  Pos target = findCh('T');
  //start.display("S");
  //start.display("T");
  queue<Pos> Q;
  Q.push(start);
  tick[start.x][start.y][start.color][start.dir] = 0;
  while (Q.size()){
    Pos s = Q.front(); Q.pop();
    //s.display("Pop");
    for (int i = 0; i < 3; i++){
      Pos t = s.action(i);
      if (!t.isValid()) continue;
      if (tick[t.x][t.y][t.color][t.dir] != INF) continue;
      if (grid[t.x][t.y] == '#') continue;
      tick[t.x][t.y][t.color][t.dir] = tick[s.x][s.y][s.color][s.dir] + 1;
      Q.push(t);
      //s.display("   Push");
    }
  }
  int best = INF;
  for (int i = 0; i < 4; i++){
    target.dir = i;
    best = min(best, tick[target.x][target.y][target.color][target.dir]);
  }
  return best;
}

bool ParserCreateQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
{
    ParserKeyword s_create("CREATE");
    ParserKeyword s_temporary("TEMPORARY");
    ParserKeyword s_attach("ATTACH");
    ParserKeyword s_table("TABLE");
    ParserKeyword s_database("DATABASE");
    ParserKeyword s_if_not_exists("IF NOT EXISTS");
    ParserKeyword s_as("AS");
    ParserKeyword s_view("VIEW");
    ParserKeyword s_materialized("MATERIALIZED");
    ParserKeyword s_populate("POPULATE");
    ParserToken s_dot(TokenType::Dot);
    ParserToken s_lparen(TokenType::OpeningRoundBracket);
    ParserToken s_rparen(TokenType::ClosingRoundBracket);
    ParserStorage storage_p;
    ParserIdentifier name_p;
    ParserColumnsOrIndicesDeclarationList columns_or_indices_p;
    ParserSelectWithUnionQuery select_p;

    ASTPtr database;
    ASTPtr table;
    ASTPtr columns_list;
    ASTPtr to_database;
    ASTPtr to_table;
    ASTPtr storage;
    ASTPtr as_database;
    ASTPtr as_table;
    ASTPtr select;
    String cluster_str;
    bool attach = false;
    bool if_not_exists = false;
    bool is_view = false;
    bool is_materialized_view = false;
    bool is_populate = false;
    bool is_temporary = false;

    if (!s_create.ignore(pos, expected))
    {
        if (s_attach.ignore(pos, expected))
            attach = true;
        else
            return false;
    }

    if (s_temporary.ignore(pos, expected))
    {
        is_temporary = true;
    }

    if (s_table.ignore(pos, expected))
    {
        if (s_if_not_exists.ignore(pos, expected))
            if_not_exists = true;

        if (!name_p.parse(pos, table, expected))
            return false;

        if (s_dot.ignore(pos, expected))
        {
            database = table;
            if (!name_p.parse(pos, table, expected))
                return false;
        }

        if (ParserKeyword{"ON"}.ignore(pos, expected))
        {
            if (!ASTQueryWithOnCluster::parse(pos, cluster_str, expected))
                return false;
        }

        // Shortcut for ATTACH a previously detached table
        if (attach && (!pos.isValid() || pos.get().type == TokenType::Semicolon))
        {
            auto query = std::make_shared<ASTCreateQuery>();
            node = query;

            query->attach = attach;
            query->if_not_exists = if_not_exists;
            query->cluster = cluster_str;

            getIdentifierName(database, query->database);
            getIdentifierName(table, query->table);

            return true;
        }

        /// List of columns.
        if (s_lparen.ignore(pos, expected))
        {
            if (!columns_or_indices_p.parse(pos, columns_list, expected))
                return false;

            if (!s_rparen.ignore(pos, expected))
                return false;

            if (!storage_p.parse(pos, storage, expected) && !is_temporary)
                return false;
        }
        else
//.........这里部分代码省略.........