POJ_3111_K_Best

 1 #include<cstdio>
 2 #include<algorithm>
 3 using std :: sort;
 4 using std :: max;
 5 
 6 const int maxn=100005,INF=0x7fffffff;
 7 int n,k;
 8 int ans[maxn];
 9 struct point
10 {
11     int a,b,num;
12     double c;
13 }j[maxn];
14 double x,y;
15 
16 bool comp(point x,point y) { return x.c>y.c; }
17 
18 bool C(double x)
19 {
20     for(int i=1;i<=n;i++) j[i].c=j[i].a-j[i].b*x;
21     sort(j+1,j+n+1,comp);
22     double sum=0;
23     for(int i=1;i<=k;i++) sum+=j[i].c;
24     return sum>=0;
25 }
26 
27 void solve()
28 {
29     for(int i=0;i<25;i++)
30     {
31         double m=x+(y-x)/2;
32         if(C(m))
33         {
34             x=m;
35             for(int i=1;i<=k;i++) ans[i]=j[i].num;
36         }
37         else y=m;
38     }
39     for(int i=1;i<k;i++) printf("%d ",ans[i]);
40     printf("%d",ans[k]);
41 }
42 
43 void init()
44 {
45     scanf("%d%d",&n,&k);
46     for(int i=1;i<=n;i++) 
47     {
48         scanf("%d%d",&j[i].a,&j[i].b);
49         j[i].num=i;
50         y=max(y,(double)j[i].a/(double)j[i].b);
51     }
52 }
53 
54 int main()
55 {
56     freopen("k.in","r",stdin);
57     freopen("k.out","w",stdout);
58     init();
59     solve();
60     fclose(stdin);
61     fclose(stdout);
62     return 0;
63 }