Solution: Create a large online communication tool, similar to the instant messaging tools similar to QQ, which are different from it, depending on the level. The user can submit the problem that the same level is automatically submitted from the same level. It cannot be resolved. The first level is automatically submitted, and the class is pushed until solves or cancels. If it is unable to solve, then the difficulty list 1, the difficulty list: special area, solve this area The problem will be very high. 2, advance:
