cf 758D - Ability To Convert

从后往前贪心就好了。各种各样0的情况太BT了。。

（各种爆long long，f**k）

 #include<bits/stdc++.h>
 #define LL long long
 #define N 100005
 #define lowbit(x) x&(-x)
 using namespace std;
 inline int ra()
 {
     int x=,f=; char ch=getchar();
     while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}
     while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}
     return x*f;
 }
 LL n,m=,ans;
 string s;
 LL get(int l, int r)// int boom!!
 {
     LL sum=;
     for (int i=l; i<=r; i++)
     {
         sum=sum*+s[i]-'';
         if (sum>n) break;
     }
     return sum;
 }
 int main()
 {
     n=(LL)ra(); cin>>s;
     int len=s.length();
     int last=len-,i=len-;
     while (i!=-)
     {
         if (s[i]!='' && get(i,last)<n)
         {
             i--;
             if (i==-)
             {
                 ans+=m*get(,last);
                 break;
             }
             continue;
         }
         if (s[i]=='')
         {
             int j=i;
             while (j!=- && get(j,last)<n && s[j]=='') j--;
             while (s[last]=='' && get(j,last)>=n) m=m*n,last--;
             if (s[j]!='' && get(j,last)<n) i=j;
             if (s[j]!='' && get(j,last)>=n)
             {
                 ans+=m*get(i,last);
                 last=i;
                 m=m*n;
             }
         }
         if (s[i]!='' && get(i,last)>=n)
         {
             ans+=m*get(i+,last);
             last=i;
             m*=n;
         }
     }
     cout<<ans;
     return ;
 }