Educational Codeforces Round 81 (Rated for Div. 2) C.Obtain The String

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define rg register ll
int main()
{
    ll n;
    cin>>n;
    for(rg i=1;i<=n;i++)
    {
        string s,t;
        vector<ll>v[30];
        cin>>s>>t;
        for(rg j=0;s[j];j++)
        {
            v[s[j]-'a'].push_back(j);
        }
        ll ans=1,tep=-1;
        for(rg j=0;t[j];j++)
        {
            ll k=t[j]-'a';
            if(!v[k].size())
            {
                ans=-1;
                break;
            }
            else
            {
                if(v[k][v[k].size()-1]>tep)
                {
                    //cout<<*upper_bound(v[k].begin(),v[k].end(),tep)<<endl;
                    tep=v[k][upper_bound(v[k].begin(),v[k].end(),tep)-v[k].begin()];
                }
                else ans++,tep=v[k][0];
            }
        }
        cout<<ans<<endl;
    }
    while(1)getchar();
    return 0;
}