洛谷—— P1577 切绳子

 1 #include <algorithm>
 2 #include <cstdio>
 3 
 4 inline void read(int &x)
 5 {
 6     x=0; register char ch=getchar();
 7     for(; ch>‘9‘||ch<‘0‘; ) ch=getchar();
 8     for(; ch>=‘0‘&&ch<=‘9‘; ch=getchar()) x=x*10+ch-‘0‘;
 9 }
10 
11 const int N(10005);
12 
13 double ans,z;
14 int n,k,len[N];
15 
16 int L,R,Mid;
17 inline bool check(int x)
18 {
19     int cnt=0;
20     for(int i=n; i; --i)
21     {
22         if(cnt>=k) return 1;
23         if(len[i]/x<1) return 0;
24         cnt+=len[i]/x;
25     }
26     return cnt>=k;
27 }
28 
29 int Presist()
30 {
31     read(n),read(k);
32     for(int i=1; i<=n; ++i)
33         scanf("%lf",&z),len[i]=z*100;
34     std:: sort(len+1,len+n+1);
35     for(L=1,R=len[n]; L<=R; )
36     {
37         Mid=L+R>>1;
38         if(check(Mid))
39         {
40             ans=Mid*1./100;
41             L=Mid+1;
42         }
43         else R=Mid-1;
44     }
45     printf("%.2lf\n",ans);
46     return 0;
47 }
48 
49 int Aptal=Presist();
50 int main(int argc,char**argv){;}