题目大意: 有$n(n\le2\times10^5)$张卡片排成一排,每张卡片正反面有两个数$a_i$和$b_i$.$m(m\le10^6)$次操作,每次交换第$c_i$和第$d_i$张卡片,问若可以任意翻转卡片,是否存在一种方案使得卡片上的数字构成一个不下降序列. 思路: 用线段树维护区间,左端点取最大/小值时,右端点取最大值还是最小值. #include<cstdio> #include<cctype> #include<algorithm> inline int…

题目链接:Cards 听说这道题是染色问题的入门题,于是就去学了一下\(Bunside\)引理和\(P\acute{o}lya\)定理(其实还是没有懂),回来写这道题. 由于题目中保证"任意多次洗牌都可用这\(m\)种洗牌法中的一种代替",于是有了封闭性. 结合律显然成立. 题目中还保证了"对每种洗牌法,都存在一种洗牌法使得能回到原状态",逆元也有了. 只剩下一个单位元,我们手动补上.单位元就是不洗牌. 所以所有的洗牌方案构成了一个置换群.于是就可以用$Bunsid…

E. Vladik and cards time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Vladik was bored on his way home and decided to play the following game. He took n cards and put them in a row in front…

3524: [Poi2014]Couriers Time Limit: 20 Sec  Memory Limit: 256 MBSubmit: 1892  Solved: 683[Submit][Status][Discuss] Description 给一个长度为n的序列a.1≤a[i]≤n.m组询问,每次询问一个区间[l,r],是否存在一个数在[l,r]中出现的次数大于(r-l+1)/2.如果存在,输出这个数,否则输出0. Input 第一行两个数n,m.第二行n个数,a[i].接下来m行,…

1004: [HNOI2008]Cards Description 小春现在很清闲,面对书桌上的N张牌,他决定给每张染色,目前小春只有3种颜色:红色,蓝色,绿色.他询问Sun有 多少种染色方案,Sun很快就给出了答案.进一步,小春要求染出Sr张红色,Sb张蓝色,Sg张绝色.他又询问有多少种方 案,Sun想了一下,又给出了正确答案. 最后小春发明了M种不同的洗牌法,这里他又问Sun有多少种不同的染色方案. 两种染色方法相同当且仅当其中一种可以通过任意的洗牌法(即可以使用多种洗牌法,而每种方法可以使…

C. Hongcow Buys a Deck of Cards time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output One day, Hongcow goes to the store and sees a brand new deck of n special cards. Each individual card is eit…

3524: [Poi2014]Couriers Time Limit: 20 Sec  Memory Limit: 256 MBSubmit: 1905  Solved: 691[Submit][Status][Discuss] Description 给一个长度为n的序列a.1≤a[i]≤n.m组询问,每次询问一个区间[l,r],是否存在一个数在[l,r]中出现的次数大于(r-l+1)/2.如果存在,输出这个数,否则输出0. Input 第一行两个数n,m.第二行n个数,a[i].接下来m行,…

题目链接: 传送门 Little Elephant and Cards time limit per test:2 second     memory limit per test:256 megabytes Description The Little Elephant loves to play with color cards. He has n cards, each has exactly two colors (the color of the front side and the…

题目链接: 传送门 Invitation Cards Time Limit: 5000MS     Memory Limit: 32768 K Description In the age of television, not many people attend theater performances. Antique Comedians of Malidinesia are aware of this fact. They want to propagate theater and, mo…

E. George and Cards   George is a cat, so he loves playing very much. Vitaly put n cards in a row in front of George. Each card has one integer written on it. All cards had distinct numbers written on them. Let's number the cards from the left to the…