ldub

-- counts the number of shielded zcash transactions sent between 2019-01-01 to 2019-05-29
SELECT COUNT(*) AS num_shielded_txs FROM `bigquery-public-data.crypto_zcash.transactions` AS zec_txs
WHERE
  zec_txs.is_coinbase = FALSE
  AND zec_txs.block_timestamp >= '2019-01-01'
  AND zec_txs.block_timestamp <= '2019-05-29'
  AND (zec_txs.input_count = 0
    OR zec_txs.output_count = 0
    OR EXISTS (SELECT 1 FROM UNNEST(zec_txs.inputs) WHERE type = 'shielded')
    OR EXISTS (SELECT 1 FROM UNNEST(zec_txs.outputs) WHERE type = 'shielded'))

ldub

first two transactions from 0x6B477781b0e68031109f21887e6B5afEAaEB002b:

1. 0xd79fc80e7b787802602f3317b7fe67765c14a7d40c3e0dcb266e63657f8813961
2. 0x061bf0b4b5fdb64ac475795e9bc5a3978f985919ce6747ce2cfbbcaccaf51009

lets ask infura for more information...

λ curl -X POST --data '{"jsonrpc":"2.0","method":"eth_getTransactionByHash","params":["0x061bf0b4b5fdb64ac475795e9bc5a3978f985919ce6747ce2cfbbcaccaf51009"],"id":1}' https://ropsten.infura.io/v3/

{
    "jsonrpc": "2.0",

ldub

Keybase proof

I hereby claim:

• I am ldub on github.
• I am dubinets (https://keybase.io/dubinets) on keybase.
• I have a public key ASCFyLfBTpZFU_Iihxb402Mnse-EZHIF63q9ECfh_SJNMAo

To claim this, I am signing this object:

ldub

// Transpose does this
// {1, 2, 3, 4}        {1, 5,  9}
// {5, 6, 7, 8}   ==>  {2, 6, 10}
// {9,10,11,12}        {3, 7, 11}
//                    {4, 8, 12}
void Main()
{
    List<List<int>> list = new List<List<int>>() {
        new List<int>() {1, 2, 3, 4},
        new List<int>() {5, 6, 7, 8},

ldub

import java.io.BufferedReader;
import java.io.InputStreamReader;
 
public class Shuffle {
    public static void main(String[] args) {
        String str = "shuf_ftw";
        try {
            String shuffled = (new BufferedReader(new InputStreamReader(Runtime.getRuntime().exec(new String[] { "sh", "-c", "echo " + str + " | fold -w1 | shuf | tr -d '\n'" }).getInputStream()))).readLine();
            
            System.out.println(shuffled);

ldub

This is an excersize in point-free Haskell.

To create a function that adds two numbers we could write:
λ> let f a b = a + b
Or alternatively
λ> let f = (+)

Now, how about a function that adds three numbers? 
λ> let g = (+) . (+) --Doesn't work

ldub

Given an array of N points in a plane, find the circle which contains the maximum numbers of the given points on its perimiter.
 
for each pair of points {                                               // O(N^2)
  for each of the N-2 remaining points {                                // O(N)
    compute radius and center of circle defined by the 3 chosen points
  }
  sort list by radius                                                   // O(N*log(N))
  filter list by (most common radius) and (most common center)          // O(N)              ? is it O(N)?
  return (radius, center x, center y, number of matching circles);
}