poj 3040 Allowance

 1 #include<algorithm>
 2 #include<cstdio>
 3 #include<iostream>
 4 #include<cstring>
 5 using namespace std;
 6 struct TT
 7 {
 8     int  v,w;
 9 }a[25];
10 int need[25];
11 bool cmp(TT m, TT n)
12 {
13   if(m.v>n.v) return true;
14          return false;
15 }
16 int main()
17 {
18     int n,i,k;
19     int value,aa,bb,ans;
20     while(~scanf("%d %d",&n,&value))
21     {
22         ans = 0;
23         k = 0;
24         for( i=0;i<n;i++)
25         {
26             scanf("%d %d",&aa,&bb);//排除大数；
27             if( aa>= value)
28             {
29                  ans = ans+bb;
30             }
31             else
32              {
33                  a[k].v = aa;
34                  a[k].w = bb;
35                  k++;
36              }
37         }
38         //k = n;
39         //printf("sdfgsdf\n");
40         sort(a,a+k,cmp);
41         while(1)
42         {
43             memset(need,0,sizeof(need));
44             int sum = value;
45             for(int i=0; i<k; i++) // Õý×ÅÕÒ
46             {
47                 int tmp = sum/a[i].v;
48                 need[i] = min(a[i].w,tmp);
49                 sum = sum - a[i].v*need[i];
50             }
51             if(sum>0)
52             {
53                 for(int i=k-1;i>=0;i--)
54                 {
55                     if(a[i].w && a[i].v>=sum)
56                     {
57                         need[i]++;
58                         sum = 0;
59                         break;
60                     }
61                 }
62             }
63             if(sum>0) break;
64             int s = 0x3f3f3f3f;
65             for(int i=0;i<k;i++)
66             {
67                 if(need[i])
68                     s = min(s,a[i].w/need[i]);
69             }
70             ans = ans+s;
71             for(int i=0;i<k;i++)
72             {
73                 if(need[i])
74                     a[i].w -= need[i]*s;
75             }
76         }
77         printf("%d\n",ans);
78     }
79     return 0;
80 }