How to declare global hashmap for slices?

[AchalaSB]

Hi,
How we can declare global hashmap?
In my use case I want to insert some value to the key in init function and then using transfer function I want to transfer amount. At the time i have to modify the new state.
(PS: I'm want to compile this code into wasm and use that binary in Go, So using FFI in my code and make it as memory pointers)

https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=ad466c07c08b4177f9c675c5116bbc63

Above code is failed due to type errors

 Compiling playground v0.0.1 (/playground)
warning: unused `#[macro_use]` import
 --> src/main.rs:1:1
  |
1 | #[macro_use]
  | ^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

error[E0308]: mismatched types
  --> src/main.rs:20:20
   |
20 |     HASHMAP.insert(sen, 100000);
   |                    ^^^ expected `i32`, found slice `[i32]`
   |
   = note: expected reference `&'static i32`
              found reference `&[i32]`

error[E0277]: the trait bound `&i32: std::borrow::Borrow<&[i32]>` is not satisfied
  --> src/main.rs:35:40
   |
35 |     let sender_balance = match HASHMAP.get(&sen) {
   |                                        ^^^ the trait `std::borrow::Borrow<&[i32]>` is not implemented for `&i32`

error[E0308]: mismatched types
  --> src/main.rs:45:24
   |
45 |         HASHMAP.insert(sen, sender_balance - amount);
   |                        ^^^ expected `i32`, found slice `[i32]`
   |
   = note: expected reference `&'static i32`
              found reference `&[i32]`

error[E0277]: the trait bound `&i32: std::borrow::Borrow<&[i32]>` is not satisfied
  --> src/main.rs:46:47
   |
46 |         let recipient_balance = match HASHMAP.get(&recp) {
   |                                               ^^^ the trait `std::borrow::Borrow<&[i32]>` is not implemented for `&i32`

error[E0308]: mismatched types
  --> src/main.rs:51:24
   |
51 |         HASHMAP.insert(recp, recipient_balance + amount);
   |                        ^^^^ expected `i32`, found slice `[i32]`
   |
   = note: expected reference `&'static i32`
              found reference `&[i32]`

error: aborting due to 5 previous errors

Some errors have detailed explanations: E0277, E0308.
For more information about an error, try `rustc --explain E0277`.
error: could not compile `playground`.

To learn more, run the command again with --verbose.

please help me in reading/ inserting new value

TIA