一眼看出是完全背包
设f[i]表示哞哞叫总音量为i时最少需要几头奶牛
a[i]为在第i个草场听到的哞哞叫总音量
则第i个草场自己的哞哞叫音量为a[i]-a[i-1]-1
代码呼之欲出
uses math;
var
f:array[1..100000]of longint;
v:array[1..100]of longint;
a:array[1..20]of longint;
n,b,i,j,s:longint;
begin
fillchar(f,sizeof(f),127);
read(n,b);
for i:=1 to n do read(v[i]);
for i:=1 to b do read(a[i]);
for i:=1 to b do
for j:=v[i]to 100000 do f[j]:=min(f[j],f[j-v[i]]+1);
a[0]:=1;
for i:=1 to n do
begin
inc(s,f[a[i]-a[i-1]+1]);
if a[i]=0 then a[i]:=1;
end;
if s>100000 then write(-1)else write(s);
end.