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）

 1 #include<bits/stdc++.h>
 2 #define LL long long
 3 #define N 100005
 4 #define lowbit(x) x&(-x)
 5 using namespace std;
 6 inline int ra()
 7 {
 8     int x=0,f=1; char ch=getchar();
 9     while (ch<‘0‘ || ch>‘9‘) {if (ch==‘-‘) f=-1; ch=getchar();}
10     while (ch>=‘0‘ && ch<=‘9‘) {x=x*10+ch-‘0‘; ch=getchar();}
11     return x*f;
12 }
13 LL n,m=1,ans;
14 string s;
15 LL get(int l, int r)// int boom!!
16 {
17     LL sum=0;
18     for (int i=l; i<=r; i++)
19     {
20         sum=sum*10+s[i]-‘0‘;
21         if (sum>n) break;
22     }
23     return sum;
24 }
25 int main()
26 {
27     n=(LL)ra(); cin>>s;
28     int len=s.length();
29     int last=len-1,i=len-1;
30     while (i!=-1)
31     {
32         if (s[i]!=‘0‘ && get(i,last)<n)
33         {
34             i--;
35             if (i==-1)
36             {
37                 ans+=m*get(0,last);
38                 break;
39             }
40             continue;
41         }
42         if (s[i]==‘0‘)
43         {
44             int j=i;
45             while (j!=-1 && get(j,last)<n && s[j]==‘0‘) j--;
46             while (s[last]==‘0‘ && get(j,last)>=n) m=m*n,last--;
47             if (s[j]!=‘0‘ && get(j,last)<n) i=j;
48             if (s[j]!=‘0‘ && get(j,last)>=n)
49             {
50                 ans+=m*get(i,last);
51                 last=i;
52                 m=m*n;
53             }
54         }
55         if (s[i]!=‘0‘ && get(i,last)>=n)
56         {
57             ans+=m*get(i+1,last);
58             last=i;
59             m*=n;
60         }
61     }
62     cout<<ans;
63     return 0;
64 }