luogu1541 乌龟棋 (dp)

dp..dp的时候不能设f[N][x1][x2][x3][x4]，会T，要把N省略，然后通过1/2/3/4牌的数量来算已经走到哪一个了

 #include<bits/stdc++.h>
 #define pa pair<int,int>
 #define ll long long
 using namespace std;
 const int maxn=,maxm=;

 inline ll rd(){
     ll x=;char c=getchar();int neg=;
     while(c<''||c>''){if(c=='-') neg=-;c=getchar();}
     while(c>=''&&c<='') x=x*+c-'',c=getchar();
     return x*neg;
 }

 int N,M,m[];
 int f[maxm][maxm][maxm][maxm];
 bool flag[][][maxm];
 int v[maxn];

 inline void sm(int &a,int b){
     if(b>a) a=b;
 }

 int main(){
     int i,j,k;
     N=rd(),M=rd();
     for(i=;i<N;i++) v[i]=rd();
     for(i=;i<=M;i++) m[rd()]++;
     f[][][][]=v[];
     for(int x1=;x1<=m[];x1++){
         for(int x2=;x2<=m[];x2++){
             for(int x3=;x3<=m[];x3++){
                 for(int x4=;x4<=m[];x4++){
                     int now=f[x1][x2][x3][x4],pos=x1*+x2*+x3*+x4*;
                     if(x1<m[]) sm(f[x1+][x2][x3][x4],now+v[pos+]);
                     if(x2<m[]) sm(f[x1][x2+][x3][x4],now+v[pos+]);
                     if(x3<m[]) sm(f[x1][x2][x3+][x4],now+v[pos+]);
                     if(x4<m[]) sm(f[x1][x2][x3][x4+],now+v[pos+]);
                 }
             }
         }
     }printf("%d\n",f[m[]][m[]][m[]][m[]]);
     return ;
 }