C. Obtain The String-(二分)

总结

第一步
把相同字母的下标放在一个一维数组
第二步
二分跑是否存在即可

/*
                ____________    ______________       __
               / _________  /\ /_____   _____/\     / /\
              / /\       / /  \\    /  /\    \ \   / /  \
             / /  \_____/ /   / \__/  /  \____\/  / /   /
            / /   /    / /   /    /  /   /       / /   /
           / /   /    / /   /    /  /   /       / /   /
          / /   /    / /   /    /  /   /       / /   /
         / /___/____/ /   /    /  /   /       / /___/________
        /____________/   /    /__/   /       /______________/\
        \            \  /     \  \  /        \              \ \
         \____________\/       \__\/          \______________\/
           ___       ___               ___    __________
          /  /\     /  /\             /  /\  /_______  /\
         /  /__\___/  /  \           /  /  \ \      /  /  \
        /____    ____/   /          /  /   /  \____/  /   /
        \   /   /\   \  /          /  /   /       /  /   /
         \_/   /  \___\/ ___      /  /   /       /  /   /
          /   /   /     /  /\    /  /   /       /  /   /
         /   /   /     /  /__\__/  /   /       /  /___/____
        /___/   /     /___________/   /       /___________/\
        \   \  /      \           \  /        \           \ \
         \___\/        \___________\/          \___________\/

          A CODE OF CBOY

*/
#include<bits/stdc++.h>
//typedef long long ll;
//#define ull       unsigned long long
//#define int       long long
#define F           first
#define S           second
#define endl        "\n"//<<flush
#define lowbit(x)   (x&(-x))
#define ferma(a,b)  pow(a,b-2)
#define pb          push_back
#define mp          make_pair
#define all(x)      x.begin(),x.end()
#define memset(a,b) memset(a,b,sizeof(a));
#define IOS         ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
using namespace std;
const double PI=acos(-1.0);
const int inf=0x3f3f3f3f;
const int MAXN=0x7fffffff;
const long long INF = 0x3f3f3f3f3f3f3f3fLL;
void file()
{
#ifdef ONLINE_JUDGE
#else
    freopen("cin.txt","r",stdin);
    //  freopen("cout.txt","w",stdout);
#endif
}
int vis[26];
signed main()
{
    IOS;
    //file();
    int t;
    cin>>t;
    while(t--)
    {
        vector<int>vec[26],vis(26);
        string s,t;
        cin>>s>>t;
        for(auto &it:s)
            vec[it-'a'].pb(&it-&*s.begin());
        for(int i=0;i<26;i++)
            vis[i]=vec[i].size();
        int flag=0,ans=0,index=-1;
        for(int i=0;i<t.size();i++)
        {
            int num=t[i]-'a';
            int pos=upper_bound(all(vec[num]),index)-vec[num].begin();
            if(pos==vis[num]&&index==-1)
            {
                flag=1;
                break;
            }
            else if(pos==vis[num])
            {
                index=-1;
                ans++;
                i--;
            }
            else
            {
                index=vec[num][pos];
            }
        }
        if(flag)
            cout<<-1<<endl;
        else
            cout<<ans+1<<endl;
    }
    return 0;
}