Codeforces 835B - The number on the board Solution

  Solution in C++:

 ///La ilaha illellahu muhammadur rasulullah

///******Bismillahir-Rahmanir-Rahim******///

///AH Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh

1. #include <bits/stdc++.h>
2. #define ll long long
3. using namespace std;
4. int main()
5. {
6. ll n,k,i,ss=0,r=0;
7. string s;
8. cin>>k>>s;
9. sort(s.begin(),s.end());
10. for(i=0;i<s.size();i++)
11. ss+=s[i]-'0';
12. for(i=0;i<s.size();i++)
13. {
14. if(ss>=k)
15. break;
16. while(s[i]<'9')
17. {
18. ss++;
19. s[i]++;
20. }
21. r++;
22. }
23. cout<<r<<endl;
24. }