Zoj-2921 stock ***

1/* pure turn, http://hi.baidu.com/sheep_finalfreedom/blog/item/1fbb2046408dd889b3b7dc4a.html */

2 /*
3 http://acm.zju.edu.cn/onlinejudge/showProblem.do? Problemcode = 2921.
4
5 initially thought it was DP. Later I figured it out and found it was a classic greedy!
6
7. The strategy is to sell the product from the last day!
8
9 although the stock on the last day may include the stock that has not been sold for the past few days,
10 but the price of the day is the same for every stock,
11. Therefore, we use a greedy policy,
12 first, how much can I sell my own stock on the last day,
13. If you can sell it again after sales,
14. Add the quota to the last day,
15 In this way, the last day of the stock has two options,
16. The price of the last day or the price of the last day,
17 of course, it is the best price to sell,
18 if there is still a quota after the sale, it will be added to the last three days,
19 and so on
20
21. Use the priority queue when adding a quota. Each Pop will throw the highest price quota!
22 *
23 */
24 # include <iostream>
25 # include <queue>
26 using namespace STD;
27
28 struct share
29 {
30 int price, size;
31 friend bool operator <(share N1, share N2)
32 {
33 return n1.price <n2.price;
34}
35 };
36 priority_queue <share> q;
37
38 int G [100001];
39 int P [100001];
40 int s [100001];
41
42 int main ()
43 {
44 // freopen ("Debug \ in.txt", "r", stdin );
45 int repeat, M, I;
46 int total, temp;
47 share tt;
48 CIN> repeat;
49 while (Repeat --)
50 {
51 CIN> m;
52 for (I = 1; I <= m; I ++)
53 scanf ("% d", & G [I], & P [I], & S [I]);
54
55 while (! Q. Empty ())
56 Q. Pop ();
57 total = 0;
58 for (I = m; I> = 1; I --)
59 {
60 TT. Price = P [I];
61 TT. size = s [I];
62 Q. Push (TT );
63 temp = G [I];
64 While (! Q. Empty () & temp)
65 {
66 TT = Q. Top ();
67 Q. Pop ();
68 if (temp> = TT. Size)
69 {
70 temp-= TT. size;
71 total + = TT. Size * TT. price;
72}
73 else
74 {
75 total + = temp * TT. price;
76 TT. size = TT. Size-temp;
77 Q. Push (TT );
78 temp = 0;
79
80
81}
82}
83
84}
85 cout <total <Endl;
86}
87
88 return 0;
89}