CF85D.Sum of Medians
普及/提高-
通过率:0%
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题目描述
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 a_{1}<a_{2}<a_{3}<...<a_{k} , 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.
输入格式
The first line contains number n ( 1<=n<=105 ), the number of operations performed.
Then each of n lines contains the description of one of the three operations:
- 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 add x operation it is true that the element x is not included in the set directly before the operation.
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 .
输出格式
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).
输入输出样例
输入#1
6 add 4 add 5 add 1 add 2 add 3 sum
输出#1
3
输入#2
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
输出#2
5 11 13