1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <cmath> 5 #include <algorithm> 6 #include <string> 7 #include <vector> 8 #include <set> 9 #include <map> 10 #include <stack> 11 #include <queue> 12 #include <sstream> 13 #include <iomanip> 14 using namespace std; 15 typedef long long LL; 16 const int INF = 0x4fffffff; 17 const double EXP = 1e-5; 18 const int MS = 40005; 19 const int SIZE = 100005; 20 21 int main() 22 { 23 LL A,B,n; 24 LL L,T,M; 25 cin>>A>>B>>n; 26 for(LL i=0;i<n;i++) 27 { 28 cin>>L>>T>>M; 29 LL minv=(L-1)*B+A; 30 if(T<minv) 31 { 32 cout<<"-1"<<endl; 33 continue; 34 } 35 LL R=(T-minv)/B; 36 37 int tl=L; 38 int tr=L+R+1; 39 while((tr-tl)>1) //二分查找用[a,b)使用方便，又不易出错。 40 { 41 LL mid=(tr+tl)>>1; 42 LL sum=(mid-L+1)*A+(mid+L-2)*(mid-L+1)/2*B; 43 LL maxv=(mid-1)*B+A; 44 45 LL time=sum/M; 46 if(sum%M!=0) 47 time++; 48 time=max(time,maxv); 49 if(time<=T) 50 tl=mid; 51 else 52 tr=mid; 53 } 54 cout<<tl<<endl; 55 } 56 return 0; 57 }