694297232

摘要： 描述Astronomers often examine star maps where stars are represented by points on a plane and each star has Cartesian coordinates. Let the level of a star be an amount of the stars that are not higher and not to the right of the given star. Astronomers want to know the distribution of the levels of the 阅读全文

摘要： 描述 Bob always plays game with Alice.Today,they are playing a game on a tree.Alice has m1 stones,Bob has m2 stones.At the beginning of the game,all the stones are placed on the nodes of a tree,except the root.Alice moves first and they turns moving the stones.On each turn,the player chooses exactly o 阅读全文