Tetris is NP-Hard
Tetris is NP-Hard. Let me explain, in English, what that means. The toughness of problems is how much time it takes to solve them. Adding two 3-digit number takes less time than adding two 30-digit numbers, and hence is easier. Similarly, figuring out if a 3-digit number is prime or not is easier than a 30-digit number. Some problems grow tough very quickly. Adding two 30-digit numbers is 10-times slower than adding two 3-digit numbers. But checking if a 30-digit number is prime is several trillions of times slower than checking a 3-digit number. That is because, to check if a number is prime, you need to repeatedly divide it by numbers smaller than it. For a 3-digit number, you need to divide by around 1,000 numbers. For a 30 digit number, it’s several trillions. ...