UVa 12266 Stock Prices (优先队列)

12266 - Stock Prices

Time limit: 3.000 seconds 

http://uva.onlinejudge.org/index.php?option=onlinejudge&page=show_problem&problem=3418

In this problem we deal with the calculation of stock prices. You need to know the following things about stock prices:

• The ask price is the lowest price at which someone is willing to sell a share of a stock.
• The bid price is the highest price at which someone is willing to buy a share of a stock.
• The stock price is the price at which the last deal was established.

Whenever the bid price is greater than or equal to the ask price, a deal is established. A buy order offering the bid price is matched with a sell order demanding the ask price, and shares are exchanged at the rate of the ask price until either the sell order or the buy order (or both) is fulfilled (i.e., the buyer wants no more stocks, or the seller wants to sell no more stocks). You will be given a list of orders (either buy or sell) and you have to calculate, after each order, the current ask price, bid price and stock price.

Input

On the first line a positive integer: the number of test cases, at most 100. After that per test case:

• One line with an integer n (1 ≤ n ≤ 1 000): the number of orders.
• n lines of the form "order_type x shares at y", whereorder_type is either "buy" or "sell", x (1 ≤ x ≤ 1 000) is the number of shares of a stock someone wishes to buy or to sell, and y (1 ≤ y ≤ 1 000) is the desired price.

Output

Per test case:

• n lines, each of the form "a_i b_i s_i", where a_i, b_i and s_i are the current ask, bid and stock prices, respectively, after the i-th order has been processed and all possible deals have taken place. Whenever a price is not defined, output "-" instead of the price.

Sample in- and output

InputOutput

26buy 10 shares at 100sell 1 shares at 120sell 20 shares at 110buy 30 shares at 110sell 10 shares at 99buy 1 shares at 1206sell 10 shares at 100buy 1 shares at 80buy 20 shares at 90sell 30 shares at 90buy 10 shares at 101sell 1 shares at 80

- 100 -120 100 -110 100 -120 110 110120 100 99- 100 120100 - -100 80 -100 90 -90 80 90100 80 90100 - 80

学英语：

after the i-th order has been processed and all possible deals have taken place.

在第i个股票订单被处理，并且所有可能的交易都发生后。

思路：用优先队列实现，buy的大的在前，sell的小的在前。

完整代码：

/*0.025s*/#include<bits/stdc++.h>using namespace std;char buff[10];struct Buy{int price, num;bool operator < (const Buy& a) const{return price < a.price;}} b;struct Sell{int price, num;bool operator < (const Sell& a) const{return price > a.price;}} s;priority_queue<Buy> buyseq;///大的在前priority_queue<Sell> sellseq;///小的在前int lastprice, delta;void update(){while (!buyseq.empty() && !sellseq.empty() && buyseq.top().price >= sellseq.top().price)///还可以继续交易{b = buyseq.top(), s = sellseq.top();buyseq.pop(), sellseq.pop();lastprice = s.price;delta = min(b.num, s.num);b.num -= delta, s.num -= delta;if (b.num > 0) buyseq.push(b);if (s.num > 0) sellseq.push(s);}}void print(){if (sellseq.empty()) printf("- ");else printf("%d ", sellseq.top().price);if (buyseq.empty()) printf("- ");else printf("%d ", buyseq.top().price);if (lastprice == -1) printf("-\n");else printf("%d\n", lastprice);}int main(){int T, n, i, num, price;scanf("%d", &T);while (T--){while (!buyseq.empty()) buyseq.pop();while (!sellseq.empty()) sellseq.pop();lastprice = -1;scanf("%d", &n);for (i = 1; i <= n; ++i){scanf("%s %d shares at %d", buff, &num, &price);if (buff[0] == 'b') buyseq.push((Buy){price, num});else sellseq.push((Sell){price, num});update();print();}}return 0;}