4071: Sum of Medians
内存限制：256 MB
时间限制：2 S
题面：传统
评测方式：文本比较
上传者：
提交：1
通过：1
题目描述
D. Sum of Medians
time limit per test
3 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
In one well-known algorithm of finding the k-th order statistics we should divide all elements into groups of five consecutive elements and find the median of each five. A median is called the middle element of a sorted array (it's the third largest element for a group of five). To increase the algorithm's performance speed on a modern video card, you should be able to find a sum of medians in each five of the array.
A sum of medians of a sorted k-element set S={a1,a2,...,ak}, where a1<a2<a3<...<ak, will be understood by as
The 
operator stands for taking the remainder, that is 
stands for the remainder of dividing x by y.
To organize exercise testing quickly calculating the sum of medians for a changing set was needed.
A sum of medians of a sorted k-element set S={a1,a2,...,ak}, where a1<a2<a3<...<ak, will be understood by as
The operator stands for taking the remainder, that is stands for the remainder of dividing x by y.
To organize exercise testing quickly calculating the sum of medians for a changing set was needed.
Input
The first line contains number n (1≤n≤105), the number of operations performed.
Then each of n lines contains the desc
- add x− add the element x to the set;
- del x− delete the element x from the set;
- sum− find the sum of medians of the set.
For any del x operation it is true that the element x is included in the set directly before the operation.
All the numbers in the input are positive integers, not exceeding 109.
Output
For each operation sum print on the single line the sum of medians of the current set. If the set is empty, print 0.
Please, do not use the %lld specificator to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams (also you may use the %I64d specificator).
Examples
Input
6 add 4 add 5 add 1 add 2 add 3 sum
Output
3
Input
14 add 1 add 7 add 2 add 5 sum add 6 add 8 add 9 add 3 add 4 add 10 sum del 1 sum
Output
5 11 13
输入样例 复制
输出样例 复制