Light OJ 1420 / DP

/***
 created: 2023-02-21-19.32.46
***/

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename U> using ordered_set=tree<U, null_type,less<U>,rb_tree_tag,tree_order_statistics_node_update>;
#define ll long long
#define all(we) we.begin(),we.end()
#define test int tt; cin>>tt; for(int cs=1;cs<=tt;cs++)
#define nl '\n'

const ll mod=1e9+7;
string a,b,c;

ll dp[101][101][101][3],v[101][101][101][3];
ll ts=1,s1,s2,s3;

ll solve(ll ai,ll bi,ll ci,ll f)
{
    if(ci==s3) return 1ll;

    if(v[ai][bi][ci][f]==ts) return dp[ai][bi][ci][f];

    ll ans=0;

    if(f==0)
    {
        ans+=solve(ai,bi,ci,1);
        if(ans>=mod) ans-=mod;
        ans+=solve(ai,bi,ci,2);
        if(ans>=mod) ans-=mod;
    }
    else if(f==1)
    {
        if(ai==s1) return 0;
        if(a[ai]==c[ci])
        {
            ans+=solve(ai+1,bi,ci+1,0);
            if(ans>=mod) ans-=mod;
        }
        ans+=solve(ai+1,bi,ci,1);
        if(ans>=mod) ans-=mod;
    }
    else
    {
        if(bi==s2) return 0;
        if(b[bi]==c[ci])
        {
            ans+=solve(ai,bi+1,ci+1,0);
            if(ans>=mod) ans-=mod;
        }
        ans+=solve(ai,bi+1,ci,2);
        if(ans>=mod) ans-=mod;
    }
    if(ans>=mod) ans-=mod;

    v[ai][bi][ci][f]=ts;
    return dp[ai][bi][ci][f]=ans;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    test
    {
        cin>>a>>b>>c;
        s1=a.size(),s2=b.size(),s3=c.size();
        cout<<"Case "<<cs<<": "<<solve(0ll,0ll,0ll,0ll)<<nl;
        ts++;
    }

    return 0;
}