[BZOJ1563][NOI2009]诗人小G(决策单调性优化DP)

模板题。

每个决策点都有一个作用区间,后来的决策点可能会比先前的优。于是对于每个决策点二分到它会比谁在什么时候更优,得到新的决策点集合与区间。

 1 #include<cstdio>
 2 #include<algorithm>
 3 #include<cstring>
 4 #define rep(i,l,r) for (int i=(l); i<=(r); i++)
 5 typedef long double ll;
 6 using namespace std;
 7 
 8 const int N=100010;
 9 const ll MAX=1e18;
10 int T,n,l,p,top;
11 ll sm[N],f[N];
12 char ch[N][35];
13 struct P{ int l,r,p; }q[N];
14 
15 ll ksm(ll x){
16     if (x<0) x=-x;
17     ll res=1; rep(i,1,p) res*=x; return res;
18 }
19 
20 ll cal(int j,int i){ return f[j]+ksm(sm[i]-sm[j]+(i-j-1)-l); }
21 
22 int find(P a,int b){
23     int l=a.l,r=a.r;
24     while (l<=r){
25         int mid=(l+r)>>1;
26         if (cal(a.p,mid)<cal(b,mid)) l=mid+1; else r=mid-1;
27     }
28     return l;
29 }
30 
31 void DP(){
32     int st=1,ed=1; q[1]=(P){0,n,0};
33     rep(i,1,n){
34         if (st<=ed && i>q[st].r) st++;
35         f[i]=cal(q[st].p,i);
36         if (st>ed || cal(i,n)<=cal(q[ed].p,n)){
37             while (st<=ed && cal(i,q[ed].l)<=cal(q[ed].p,q[ed].l)) ed--;
38             if (st>ed) q[++ed]=(P){i,n,i};
39             else{
40                 int t=find(q[ed],i);
41                 q[ed].r=t-1; q[++ed]=(P){t,n,i};
42             }
43         }
44     }
45 }
46 
47 int main(){
48     freopen("bzoj1563.in","r",stdin);
49     freopen("bzoj1563.out","w",stdout);
50     for (scanf("%d",&T); T--; ){
51         scanf("%d%d%d",&n,&l,&p);
52         rep(i,1,n) scanf("%s",ch[i]);
53         rep(i,1,n) sm[i]=sm[i-1]+strlen(ch[i]);
54         DP();
55         if (f[n]>MAX) printf("Too hard to arrange\n");
56             else printf("%lld\n",(long long)(f[n]));
57         puts("--------------------");
58     }
59     return 0;
60 }

 

posted @ 2018-10-22 23:49  HocRiser  阅读(188)  评论(0编辑  收藏  举报