BZOJ2590 [Usaco2012 Feb]Cow Coupons

 1 /**************************************************************
 2     Problem: 2590
 3     User: rausen
 4     Language: C++
 5     Result: Accepted
 6     Time:140 ms
 7     Memory:3332 kb
 8 ****************************************************************/
 9  
10 #include <cstdio>
11 #include <algorithm>
12 #include <queue>
13  
14 using namespace std;
15 typedef long long ll;
16 const int N = 50005;
17 struct data{
18     int w, v;
19     data(void){}
20     data(int x, int y) : w(x), v(y) {}
21 };
22 inline bool operator < (const data a, const data b){
23     return a.v > b.v;
24 }
25 int cnt, n, k;
26 int p[N], c[N];
27 bool vis[N];
28 ll m;
29 priority_queue <data> h, H;
30 priority_queue <ll, vector<ll>, greater<ll> > Re;
31  
32 inline int read(){
33     int x = 0;
34     char ch = getchar();
35     while (ch < ‘0‘ || ch > ‘9‘)
36         ch = getchar();
37     while (ch >= ‘0‘ && ch <= ‘9‘){
38         x = x * 10 + ch - ‘0‘;
39         ch = getchar();
40     }
41     return x;
42 }
43  
44 int main(){
45     int i;
46     ll cost;
47     data T;
48     n = read(), k = read();
49     scanf("%lld", &m);
50     for (i = 1; i <= n; ++i){
51         p[i] = read(), c[i] = read();
52         h.push(data(i, c[i]));
53         H.push(data(i, p[i]));
54     }
55     while (!Re.empty()) Re.pop();
56     for (i = 1; i <= k; ++i)
57         Re.push(0);
58     while (m > 0 && cnt < n){
59         while (vis[h.top().w])
60             h.pop();
61         while (vis[H.top().w])
62             H.pop();
63         if (Re.top() + h.top().v < H.top().v){
64             T = h.top(), cost = Re.top() + T.v;
65             if (m < cost) break;
66             m -= cost;
67             Re.pop();
68             Re.push(p[T.w] - c[T.w]);
69             vis[T.w] = 1;
70         }else{
71             T = H.top(), cost = T.v;
72             if (m < cost) break;
73             m -= cost;
74             vis[T.w] = 1;
75         }
76         ++cnt;
77     }
78     printf("%d\n", cnt);
79     return 0;
80 }