C++ :

#include <iostream>
#include <cstdio>
#include <string>
#include <algorithm>
using namespace std;
int dp[1010][1010];
int main()
{
	//freopen("in.txt", "r", stdin);
	string a, b;
	int n;
	while (cin>>n)
	{
	    while (n--)
	    {
	        cin>>a>>b;
	        for (int i=1; i<=a.size(); i++)
	        {
	            for (int j=1; j<=b.size(); j++)
	            {
	                if (a[i-1]==b[j-1])
                        dp[i][j] = dp[i-1][j-1]+1;
                    else
                        dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
	            }
	        }
	        cout<<dp[a.size()][b.size()]<<endl;
	    }
	}
	return 0;
}