giúp tớ với, nhanh nhé!

#danglam228

#include <bits/stdc++.h>
using namespace std;

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    string y,x;
    int l,r,n;
    getline(cin,y);
    cin >> n;
    for(int i=1;i<=n;i++){
        cin >> l >> r;
        cout << y.substr(l,r-l) << '\n';
    }
    return 0;
}

Code ac tối ưu nhé! 

//#pragma GCC optimize("O3","unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define empty aerialPlusPlus
#define div getoutthehereidiot
#define ms(a,val) memset(a,val,sizeof(a))
#define data stopitgetsomehelp
#define int long long
#define fastIo ios_base::sync_with_stdio(0);cin.tie(0);
#define ff first
#define ss second
#define cst const
#define pii pair<int,int>
#define pb push_back
#define ins insert
#define f(i,n) for(int i=1;i<=n;i++)
#define f2(i,n) for(int i=0;i<n;i++)
#define sf(i,beg,end,inc) for(int i=beg;i<=end;i+=inc)
#define f3(i,beg,end) for(int i=beg;i<=end;i++)
#define fd(i,n) for(int i=n;i>=1;i--)
#define fd2(i,n) for(int i=n-1;i>=0;i--)
#define sfd(i,beg,end,dec) for(int i=beg;i>=end;i-=dec)
#define fd3(i,beg,end) for(int i=beg;i>=end;i--)
#define sp(x) setprecision(x)<<fixed
#define openFile freopen("RANDOM.INP","r",stdin);freopen("RANDOM.OUT","w",stdout);
#define closeFile fclose(stdin);fclose(stdout);
#define startClock 	auto start = std::chrono::high_resolution_clock::now();
#define endClock auto end = std::chrono::high_resolution_clock::now();std::chrono::duration<double, std::milli> duration = end - start;
#define time cout<<"Time runs: "<<duration.count()<<"\n";
bool moreTest=false;
const int N=3e5+5;
string s,empty="";
int n;
string st[4*N];
void build(int i,int l,int r) {
	if(l==r) {
		st[i]=s[l];
		return ;
	}
	int m=(l+r)>>1,cl=2*i,cr=2*i+1;
	build(cl,l,m);
	build(cr,m+1,r);
	st[i]=st[cl]+st[cr];
}
string queries(int i,int l,int r,int u,int v) {
	if(l>v||r<u) {
		return empty;
	}
	if(l>=u&&r<=v) {
		return st[i];
	}
	int m=(l+r)>>1,cl=2*i,cr=2*i+1;
	return (queries(cl,l,m,u,v)+queries(cr,m+1,r,u,v));
}
void solve() {
	cin>>s;
	int n=s.size();
	s='*'+s;
	build(1,1,n);
	int t;
	cin>>t;
	while(t--) {
		int l,r;
		cin>>l>>r;
		//cout<<l+1<<" "<<r+1<<"\n";
		cout<<queries(1,1,n,l+1,r)<<"\n";
	}
}
signed main() {
	fastIo;
	int t=1;
	if(moreTest)cin>>t;
	while(t--) {
		solve();
	}
}