Create Smart Contract

Lets define compiler version and smart contract

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

contract toptenusers {
    . . . 
}

Declare variables

We will add a user struct to save invested amount by user in it and map it to user address.

struct User{
    uint256 total_invested_amount;
}
mapping(address => User) public user_info;
mapping(uint8 => address) public top_10_investors;

Algorithm

Our algorithm will assign top ten users who send token to contract in mapping created before from 1 to 10 position.

function top_10() public{
        for(uint8 i=0; i<10; i++){
            if(top_10_investors[i] == msg.sender){
                for(uint8 j=i ; j<11;j++){
                    top_10_investors[j] = top_10_investors[j+1];
                }
            }
        }
        for(uint8 i=0;i<10;i++){
            if(user_info[top_10_investors[i]].total_invested_amount < user_info[msg.sender].total_invested_amount){

                for(uint8 j = 10;j > i;j--){
                    top_10_investors[j] = top_10_investors[j-1];
                }
                top_10_investors[i] = msg.sender;
                return;
            }
        }
}

Store Function

We will need a function to trigger our top_10 function and add user amount.

function store() public payable {
        user_info[msg.sender].total_invested_amount += msg.value; 
        top_10();
}

Complete Code

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;

contract toptenusers {
   
    struct User{
        uint256 total_invested_amount;
    }
    
    mapping(address => User) public user_info;

    mapping(uint8 => address) public top_10_investors;
    
    function top_10() public{
        for(uint8 i=0; i<10; i++){
            if(top_10_investors[i] == msg.sender){
                for(uint8 j=i ; j<11;j++){
                    top_10_investors[j] = top_10_investors[j+1];
                }
            }
        }
        for(uint8 i=0;i<10;i++){
            if(user_info[top_10_investors[i]].total_invested_amount < user_info[msg.sender].total_invested_amount){

                for(uint8 j = 10;j > i;j--){
                    top_10_investors[j] = top_10_investors[j-1];
                }
                top_10_investors[i] = msg.sender;
                return;
            }
        }
    }
    
    function store() public payable {
        user_info[msg.sender].total_invested_amount += msg.value; 
        top_10();
    }
}