Order Book

B. Order Book

time limit per test
2 seconds

memory limit per test
256 megabytes

input
standard input

output
standard output

In this task you need to process a set of stock exchange orders and use them to create order book.

An order is an instruction of some participant to buy or sell stocks on stock exchange. The order number i has
price pi,
direction di —
buy or sell, and integer qi.
This means that the participant is ready to buy or sell qi stocks
at price pi for
one stock. A value qi is
also known as a volume of an order.

All orders with the same price p and direction d are
merged into one aggregated order with price p and direction d.
The volume of such order is a sum of volumes of the initial orders.

An order book is a list of aggregated orders, the first part of which contains sell orders sorted by price in descending order, the second contains buy orders also sorted by price in descending order.

An order book of depth s contains s best
aggregated orders for each direction. A buy order is better if it has higher price and a sell order is better if it has lower price. If there are less than s aggregated
orders for some direction then all of them will be in the final order book.

You are given n stock exhange orders. Your task is to print order book of depth s for
these orders.

Input

The input starts with two positive integers n and s (1 ≤ n ≤ 1000, 1 ≤ s ≤ 50),
the number of orders and the book depth.

Next n lines contains a letter di (either
'B' or 'S'), an integer pi (0 ≤ pi ≤ 105)
and an integer qi (1 ≤ qi ≤ 104)
— direction, price and volume respectively. The letter 'B' means buy, 'S'
means sell. The price of any sell order is higher than the price of any buy order.

Output

Print no more than 2s lines with aggregated orders from order book of depth s.
The output format for orders should be the same as in input.

Sample test(s)

input

6 2
B 10 3
S 50 2
S 40 1
S 50 6
B 20 4
B 25 10

output

S 50 8
S 40 1
B 25 10
B 20 4

Note

Denote (x, y) an order with price x and volume y.
There are 3 aggregated buy orders (10, 3), (20, 4), (25, 10) and two sell orders (50, 8), (40, 1) in the sample.

You need to print no more than two best orders for each direction, so you shouldn't print the order (10 3) having the worst price among buy orders.

思路：

这题不难，就是题目比较难理解，所以一直以为s，b都是从大到小。其实s排序后选后面m个，不是从开头选m个。

ac代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#include<string>
#include<cstdio>
#include<map>
using namespace std;
typedef __int64 ll;
struct node
{
char str[2];
int val;
friend bool operator<(const node& a,const node& b){
return a.str[0]>b.str[0]||(a.str[0]==b.str[0]&&a.val>b.val);
}
};
map<node,int> a;
map<node,int>::iterator it,itt;
int main()
{
/* freopen("input.txt","r",stdin);*/
int n,m,j,k,ma,cnt;
while(~scanf("%d%d",&n,&m))
{
node s;ma=0x3f3f3f3f;cnt=0;
while(n--)
{
scanf("%s%d%d",&s.str,&s.val,&k);if(s.str[0]=='S'&&!a[s])cnt++;
a[s]+=k;
}
for(j=0,k=0,itt=it=a.begin();it!=a.end()&&k<m;++it){
if(cnt>m){cnt--;continue;}
if(it->first.str[0]=='B')k++;
printf("%c %d %d\n",it->first.str[0],it->first.val,it->second);

}
printf("\n");
a.clear();
}
return 0;
}