开心铁匠铺

Problem Description Alice and Bob are playing a stone game. There are nnn piles of stones. In each turn, a player can remove some stones from a pile (the number must be positive and not greater than ...

题目链接 比赛时推了好久的容斥，结果推错了，过了样例就交了，然后A了。后来才知道这题有bug。菜啊。 题意：给定四个区间(li,ri)(li,ri)(l_i,r_i)（闭区间）,求一个四元组(x1,x2,x3,x4)(x1,x2,x3,x4)(x_1,x_2,x_3,x_4)，满足xixix_i在区间(li,ri)(li,ri)(l_i,r_i)内，且任意两个相邻的xixix_i不能相等。 ...