Code shared from the Rust Playground

playground.rs

fn main() {
    
    let mut nonces = vec![0u128];
    let mut counter = 0u64;
    nonces.pop();
    // First Gap: 1.5 x 10^9 to 2.0 x 10^9
    //counter += (2.0e9 - 1.5e9) as u64;
    for nonce in 1_500/*_000_000*/..=3_000/*_000_000*/ {
      nonces.push(nonce*1_000_000);
      counter = counter+1;
    };
    //for nonce in nonces.clone() {println!("{}",nonce);}
    
    // Second Gap: 2.5 x 10^9 to 3.0 x 10^9
    //counter += (3.0e9 - 2.5e9) as u64;
    for nonce in 2_500/*_000_000*/..=3_000/*_000_000*/ {
      nonces.push(nonce*1_000_000);
      counter = counter+1;
    };
    //for nonce in nonces.clone() {println!("{}",nonce);}
    
    // Third Gap: 3.5 x 10^9 to 4.0 x 10^9
    //counter += (4.0e9 - 3.5e9) as u64;
    for nonce in 3_500/*_000_000*/..=4_000/*_000_000*/ {
      nonces.push(nonce*1_000_000);
      counter = counter+1;
    };
    for nonce in nonces.clone() {print!("{} ",nonce);}    
    print!("\ncount={} ", counter);
    // Each gap has a size of 0.5 x 10^9
    // A more concise way to represent the total count is to sum the number of gaps and multiply by the gap size.
    // let gap_size = 0.5e9 as u64;
    // let number_of_gaps = 3;
    // let total_count = gap_size * number_of_gaps;
    
    // println!("Total count from the first method: {}", counter);
    // println!("Total count from the second method: {}", total_count);
}