| pragma solidity 0.4.21; | |
| contract ERC20Interface { | |
| function totalSupply() public constant returns (uint256); | |
| function balanceOf(address tokenOwner) public constant returns (uint256 balance); | |
| function allowance(address tokenOwner, address spender) public constant returns (uint256 remaining); | |
| function transfer(address to, uint256 tokens) public returns (bool success); | |
| function approve(address spender, uint256 tokens) public returns (bool success); | |
| function transferFrom(address from, address to, uint256 tokens) public returns (bool success); |
| [ | |
| { | |
| "anonymous": false, | |
| "inputs": [ | |
| { | |
| "indexed": true, | |
| "name": "tokenOwner", | |
| "type": "address" | |
| }, | |
| { |
GitHub Archive provides stats for projects on GitHub via a RESTful HTTP service.
Create a command-line program that lists the most active repositories for a given time range. It should support the following interface:
gh_repo_stats [--after DATETIME] [--before DATETIME] [--event EVENT_NAME] [-n COUNT]
| A SHA-256 hash contains 256 bits of data. A "Hard Hash" of difficulty N is one who's first N bits are 0. | |
| Write a program which accepts an input string, and a difficulty as it's parameters, | |
| and finds a Hard SHA-256 Hash of that difficulty for any string that includes the input string. | |
| Appending and prepending to the input string is allowed (and expected). | |
| Output the final string and the Hard Hash on stdout. | |
| Answer the following questions: | |
| What are the chances for finding a Hard Hash for difficulty N? | |
| How would you solve this problem for a massive number of strings at a very high difficulty? |
| You have a function rand5() that generates a random integer from 1 to 5. | |
| Use it to write a function rand7() that generates a random integer from 1 to 7. | |
| rand5() returns each integer with equal probability. | |
| rand7() must also return each integer with equal probability. |
| Your company delivers breakfast via autonomous quadcopter drones. And something mysterious has happened. | |
| Each breakfast delivery is assigned a unique ID, a positive integer. | |
| When one of the company's 100 drones takes off with a delivery, the delivery's ID is added to a list, | |
| delivery_id_confirmations. When the drone comes back and lands, the ID is again added to the same list. | |
| After breakfast this morning there were only 99 drones on the tarmac. One of the drones never made it back from a delivery. | |
| We suspect a secret agent from Amazon placed an order and stole one of our patented drones. | |
| To track them down, we need to find their delivery ID. | |
| Given the list of IDs, which contains many duplicate integers and one unique integer, find the unique integer. |
| Verifying that +kevlar is my openname (Bitcoin username). https://onename.com/kevlar |
| My initial understanding of this challenge is that the words needed to be found | |
| in a sequential order, but after reading the rules for Boggle, I realized that | |
| you were allowed to move in any direction at any time, so long as you didn't | |
| reuse a letter. | |
| Once I saw this, the first solution I thought of was to put all the words from a | |
| dictionary file into a tree, and then try to use the board to walk the tree, noting | |
| any leaves we encountered, but I quickly realized that this would be very memory | |
| intensive and potentially wasteful as there were bound to be a lot of words that | |
| wouldn't get used. So instead, I went for the inverse approach: |