贪心（哈夫曼树）：HDU 5884 sort

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <cstring>
 4 #include <cstdio>
 5 using namespace std;
 6 const int N=300010;
 7 int a[N],n,S,f1,f2,b1,b2;
 8 int q1[N],q2[N];
 9 bool Check(int k){
10     f1=b1=f2=b2=0;
11     for(int i=1;i<=n;i++)
12         q1[b1++]=a[i];
13     for(int i=0;(n+i-1)%(k-1);i++)
14         q2[b2++]=0;
15     int tot=0,tmp;
16     while(true){tmp=0;
17         for(int i=1;i<=k;i++){
18             if(f1==b1)tmp+=q2[f2++];
19             else if(f2==b2)tmp+=q1[f1++];
20             else if(q1[f1]<q2[f2])tmp+=q1[f1++];
21             else tmp+=q2[f2++];
22         }tot+=tmp;
23         if(f1>=b1&&f2>=b2)break;
24         q2[b2++]=tmp;
25     }    
26     return tot<=S;
27 }
28 int main(){
29     int T;
30     scanf("%d",&T);
31     while(T--){
32         scanf("%d%d",&n,&S);
33         for(int i=1;i<=n;i++){
34             scanf("%d",&a[i]);
35         }     
36         sort(a+1,a+n+1);
37         int lo=2,hi=n;
38         while(lo<=hi){
39             int mid=(lo+hi)>>1;
40             if(Check(mid))hi=mid-1;
41             else lo=mid+1;
42         }
43         printf("%d\n",lo);
44     }
45     return 0;
46 }