跟CODEVS 3415没有什么区别，也不用高精度。
http://www.cnblogs.com/autsky-jadek/p/4055184.html
1 #include<cstdio> 2 #include<cstring> 3 #include<iostream> 4 #include<algorithm> 5 using namespace std; 6 typedef long long ll; 7 ll n,dp[41][41][7],ans=-10000000000000; 8 int m,wei,len; 9 const ll Base[]= 10 {1,10,100,1000,10000,100000,1000000,10000000,100000000,1000000000, 11 10000000000,100000000000,1000000000000,10000000000000,100000000000000, 12 1000000000000000,10000000000000000,100000000000000000,1000000000000000000}; 13 ll Get_Part(const int &l,const int &r) {return n%Base[wei-l+1]/Base[wei-r];} 14 ll f(int sta,int end,int now) 15 { 16 if(dp[sta][end][now]!=-1) return dp[sta][end][now]; 17 ll res=-10000000000000; 18 if(now==2) res=max(res,Get_Part(sta,end)*f(end+1,wei,now-1)); 19 else 20 for(int i=end+1;i<=wei-(now-2);i++) 21 res=max(res,Get_Part(sta,end)*f(end+1,i,now-1)); 22 return dp[sta][end][now]=res; 23 } 24 int main() 25 { 26 scanf("%d%d",&wei,&m); cin>>n; m++; 27 if(m==1) 28 { 29 printf("%lld ",n); 30 return 0; 31 } 32 memset(dp,-1,sizeof(dp)); 33 for(int i=1;i<=wei-m+1;i++) 34 dp[wei-i+1][wei][1]=Get_Part(wei-i+1,wei); 35 for(int i=1;i<=wei-m+1;i++) 36 ans=max(ans,f(1,i,m)); 37 printf("%lld ",ans); 38 return 0; 39 }