说明：  JAVA实现的抽签算法。 你的朋友提议玩一个游戏：将写有数字的n 个纸片放入口袋中，你可以从口袋中抽取4 次纸片，每次记下纸片上的数字后都将其放回口袋中。如果这4 个数字的和是m，就是你赢，否则就是你的朋友赢。你挑战了好几回，结果一次也没赢过，于是怒而撕破口袋，取出所有纸片，检查自己是否真的有赢的可能性。
(JAVA implementation of the lottery algorithm. Your friend proposes to play a game: put a number of N pieces in your pocket. You can take 4 pieces of paper from your pocket and put them back in your pocket every time you write down the numbers on the paper. If the sum of these 4 numbers is m, you win or your friend wins. After challenging several times, you didn't win a single time, so you tore your pockets in anger and took out all the pieces of paper to see if you really had the chance of winning.)