TLE+RE,求调

#include<bits/stdc++.h>
using namespace std;
const int N=1e6+5;
int a,b;
int cnt;
int q,l,r;
int st[N][50];
int ans;
signed main(){
    cin>>a>>b;
    cin>>q;
    for(int i=1;i<=a*b;i++){
    	int u=i%a,v=i%b;
    	st[i][0]=u+v;
        ans=max(ans,st[i][0]);
	}
	for(int j=1;(1<<j)<=a*b;j++){
		for(int i=1;i<=a*b-(1<<j)+1;i++){
		    st[i][j]=max(st[i][j-1],st[i+(1<<j-1)][j-1]);
		}
	}
    while(q--){
    	cin>>l>>r;
    	cnt=0;
        if(r-l>=a*b) cout<<ans<<"\n";
    	else{
            while((1<<(cnt+1))<=r-l) cnt++;
    	    cout<<max(st[l][cnt],st[r-(1<<cnt)+1][cnt])<<"\n";
        }
	}
    return 0;
}