Solana Rust program HashMap<string, u64>

I am trying to port Ethereum DeFi contracts into Solana's Rust programs... I have learned about saving a struct or an array in programs' account data, but still do not know how to save a HashMap<address in string, amount in u64> into a program's account data... Then how to read this HashMap's values like checking each address' staked amount. Please help. Thank you!

My Solana Rust program:

pub fn get_init_hashmap() -> HashMap<&'static str, u64> {
  let mut staked_amount: HashMap<&str, u64> = HashMap::new();
  staked_amount.insert("9Ao3CgcFg3RB2...", 0);
  staked_amount.insert("8Uyuz5PUS47GB...", 0);
  staked_amount.insert("CRURHng6s7DGR...", 0);
  staked_amount
}
pub fn process_instruction(...) -> ProgramResult {
    msg!("about to decode account data");
    let acct_data_decoded = match HashMap::try_from_slice(&account.data.borrow_mut()) {
      Ok(data) => data,//to be of type `HashMap`
      Err(err) => {
        if err.kind() == InvalidData {
          msg!("InvalidData so initializing account data");
          get_init_hashmap()
        } else {
          panic!("Unknown error decoding account data {:?}", err)
        }
      }
    };
    msg!("acct_data_decoded: {:?}", acct_data_decoded);