CF707D Persistent Bookcase 洛谷评测传送门 题目描述 Recently in school Alina has learned what are the persistent data structures: they are data structures that always preserves the previous version of itself and access to it when it is modified. After reaching h…

D. Persistent Bookcase 题目连接: http://www.codeforces.com/contest/707/problem/D Description Recently in school Alina has learned what are the persistent data structures: they are data structures that always preserves the previous version of itself and a…

题目链接:http://codeforces.com/problemset/problem/707/D  有一个n*m的书架,有K个操作,求每个操作后一共有多少本书:有4种操作: 1:x y 如果 x y 位置没有书,放一本书在上面: 2:x y如果 x y 位置有书,移走: 3:x,表示把第x行的所有又书的拿走,没书的放上去: 4:k,回到第k个操作后的状态: 离线处理k个操作:当操作不为 4 时,把操作i连在i-1后,=4时把操作 i 连在a[i].x后: 这样建一棵树,然后遍历即可,在回溯…

维护一个二维零一矩阵(n,m<=1000),支持四种操作(不超过10^5次): 将(i,j)置一 将(i,j)置零 将第i行零一反转yu 回到第K次操作前的状态 每次操作后输出全局一共有多少个一 你发现如果每一次操作都复制一整行的话是可以用 $bitset$ 优化的,自带/32 所以,我们对于每一个时刻维护一个线段树,其中 $i$ 节点表示第 $i$ 行对应的 $bitset$ 编号. 对于前 $3$ 个操作,每一次操作时都暴力新建一个 bitset,然后每次在可持久化线段树上最多更新一个单点.…

Persistent Bookcase CodeForces - 707D time limit per test 2 seconds memory limit per test 512 megabytes input standard input output standard output Recently in school Alina has learned what are the persistent data structures: they are data structures…

题目链接:D Persistent Bookcase 题意:有一个n*m的书架,开始是空的,现在有k种操作: 1 x y 这个位置如果没书,放书. 2 x y 这个位置如果有书,拿走. 3 x 反转这一行,即有书的位置拿走,没书的位置放上书. 4 x 返回到第x步操作之后的书架. 现在给出q个操作,询问每次操作之后书架上书的数量. 思路: 开始没有思路.后来被告知dfs. [词不达意.参考:http://blog.csdn.net/zyjhtutu/article/details/5227949…

D. Persistent Bookcase Recently in school Alina has learned what are the persistent data structures: they are data structures that always preserves the previous version of itself and access to it when it is modified. After reaching home Alina decided…

题目链接: D. Persistent Bookcase time limit per test 2 seconds memory limit per test 512 megabytes input standard input output standard output Recently in school Alina has learned what are the persistent data structures: they are data structures that alw…

Persistent Bookcase Problem Description: Recently in school Alina has learned what are the persistent data structures: they are data structures that always preserves the previous version of itself and access to it when it is modified. After reaching…

http://codeforces.com/contest/707/problem/D 先说一下离线和在线:在线的意思就是每一个询问单独处理复杂度O(多少多少),离线是指将所有的可能的询问先一次都处理出来,最后对于每个询问O(1)回答. 然后说一下cf的这题: D. Persistent Bookcase time limit per test 2 seconds memory limit per test 512 megabytes input standard input output st…