Go: package main

import "fmt"

func main() {
	var n int
	fmt.Scan(&n)

	for q := 0; q < n; q++ {
		var s1, s2 string
		fmt.Scan(&s1, &s2)
		s1, s2 = " " + s1, " " + s2

		dp := make([][]int, len(s1))
		for i := range dp {
			dp[i] = make([]int, len(s2))
		}

		max := 0

		for i := 1; i < len(s1); i++ {
			for j := 1; j < len(s2); j++ {
				if s1[i] == s2[j] {
					dp[i][j] = dp[i-1][j-1] + 1
				} else {
					dp[i][j] = Max(dp[i-1][j], dp[i][j-1])
				}
				max = Max(max, dp[i][j])
			}
		}

		fmt.Println(max)
	}
}

func Max(n ...int) int {
	max := n[0]
	for _, v := range n[1:] {
		if v > max {
			max = v
		}
	}
	return max
}

C++: #include <cstdio>
#include <iostream>

using namespace std;

int main(){
	int q;
	scanf(" %d", &q);
	for(int i=0; i<q; ++i){
		string a, b;
		cin >> a >> b;
		
		int m=a.size(), n=b.size();
		
		string x=" "+a;
		string y=" "+b;
		
		int c[1001][1001]={0};
		for(int i=1; i<=m; ++i) c[i][0]=0;
		for(int i=1; i<=n; ++i) c[0][n]=0;
		
		int ans=0;
		for(int i=1; i<=m; ++i){
			for(int j=1; j<=n; ++j){
				if(x[i]==y[j]) c[i][j]=c[i-1][j-1]+1;
				else c[i][j]=max(c[i][j-1], c[i-1][j]);
				
				ans=max(ans,c[i][j]);		
			}
		}
		
		printf("%d\n", ans);
	}
}

C++: #include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <string>
#include <climits>
#include <tuple>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
typedef tuple< int,int,int > T;
const int MAX_N=55555;
bool is_prime[MAX_N];
int prime[MAX_N];
int main(){
  int n;
  cin>>n;
  int dp[1001][1001];
  for(int nn=0;nn<n;nn++){
    string s1,s2;
    cin>>s1>>s2;
    for(int i=0;i<1001;i++)fill(dp[i],dp[i]+1001,0);
    for(int i=0;i<s1.size();i++){
      for(int j=0;j<s2.size();j++){
        if(s1[i]==s2[j]) dp[i+1][j+1]=max(dp[i][j]+1,max(dp[i][j+1],dp[i+1][j]));
        else dp[i+1][j+1]=max(dp[i+1][j],dp[i][j+1]);
      }
    }
    cout<<dp[s1.size()][s2.size()]<<endl;
  }
  return 0;
}

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

vector<vector<int>> c(1001,vector<int>(1001));

int lcs(string &X,string &Y){
    int m=X.size();
    int n=Y.size();
    X=' '+X;
    Y=' '+Y;
    for(int i=0;i<m+1;i++) c[i][0]=0;
    for(int i=1;i<n+1;i++) c[0][i]=0;
    for(int i=1;i<m+1;i++){
        for(int j=1;j<n+1;j++){
            if(X[i]==Y[j]){
                c[i][j]=c[i-1][j-1]+1;
            }
            else{
                c[i][j]=max(c[i][j-1],c[i-1][j]);
            }
        }
    }
    return c[m][n];
}

int main(){
    int q;
    cin>>q;
    for(int i=0;i<q;i++){
        string X,Y;
        cin>>X>>Y;
        cout<<lcs(X,Y)<<endl;
    }
}

C++: #include<iostream>
#include<algorithm>
#include<string>

using namespace std;

int main(){
  string X,Y;
  int n;
  cin>>n;
  for(int m=0;m<n;m++){
  cin>>X>>Y;

  int N[X.size()+1][Y.size()+1];

  for(int i=0;i<=X.size();i++){
    for(int j=0;j<=Y.size();j++){

      N[i][j]=1;
}
  }

  /*
  for(int i=0;i<X.size();i++){
    cout<<X[i]<<endl;
  }

for(int i=0;i<Y.size();i++){
    cout<<Y[i];
  }
  */

  
for(int i=0;i<=X.size();i++){
  N[i][0]=0;
  }

for(int i=0;i<=Y.size();i++){
  N[0][i]=0;
  }

 int point;

  for(int i=1;i<=X.size();i++){
    for(int j=1;j<=Y.size();j++){
      if(X[i-1]==Y[j-1]){
	point=1;
	
      }else{
	point=0;
      }
       N[i][j]=max({N[i-1][j],N[i][j-1],N[i-1][j-1]+point});
       point=0;
}
   
  }

  cout<<N[X.size()][Y.size()];
  /*
  //answer
  for(int i=0;i<=X.size();i++){
    for(int j=0;j<=Y.size();j++){

      cout<<N[i][j]<<" ";
      if(j==Y.size()){
	cout<<endl;
      }
}
  }
  */

  }

}

C++: #include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>

#ifdef DEBUG

#define printd printf

#else

#define printd(...)

#endif


int lcs(std::string &x, std::string &y) {
    static int dp[1002][1002];

    for (int i = 0; i < x.length() + 2; i++) {
        for (int j = 0; j < y.length() + 2; j++) {
            dp[i][j] = 0;
        }
    }

    for (int i = 1; i <= x.length(); i++) {
        for (int j = 1; j <= y.length(); j++) {
            if (x[i - 1] == y[j - 1]) {
                dp[i][j] = std::max(dp[i - 1][j - 1] + 1, dp[i - 1][j]);
                dp[i][j] = std::max(dp[i][j], dp[i][j - 1]);
            } else {
                dp[i][j] = std::max(dp[i - 1][j], dp[i][j - 1]);
            }
        }
    }

    #ifdef DEBUG
    for (int i = 1; i <= x.length(); i++) {
        for (int j = 1; j <= y.length(); j++) {
            std::cout << dp[i][j] << ", ";
        }
        std::cout << std::endl;
    }
    #endif

    return dp[x.length()][y.length()];
}

int main() {
    int q;
    std::cin >> q;

    for (int qi = 0; qi < q; qi++) {
        std::string x, y;
        std::cin >> x >> y;
        std::cout << lcs(x, y) << std::endl;
    }

    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>

constexpr int nil = -1;

class ILcs
{
public:
    using vvi = std::vector<std::vector<int>>;
    virtual int lcs() = 0;
    virtual int lcs(int i1, int i2) = 0;
};

class LcsLoop : public ILcs
{
public:

    LcsLoop(std::string str1, std::string str2)
        : str1 {str1}
        , str2 {str2}
        , dp {vvi(str1.size(), std::vector<int>(str2.size()))}
    {
        CalcLcs();
    }

    int lcs() override
    {
        return lcs(str1.size() - 1, str2.size() - 1);
    }

    int lcs(int i1, int i2) override
    {
        return dp[i1][i2];
    }

private:

    std::string str1;
    std::string str2;
    vvi         dp;
    
    void CalcLcs()
    {
        for (int i = 0; i < str1.size(); ++i)
        {
            for (int j = 0; j < str2.size(); ++j)
            {
                if (i == 0 || j == 0)
                {
                    dp[i][j] = (str1[i] == str2[j]);

                    if (i == 0 && j == 0)
                        continue;

                    if (i == 0)
                        dp[i][j] = std::max(dp[i][j], dp[i][j - 1]);
                    else
                        dp[i][j] = std::max(dp[i][j], dp[i - 1][j]);
                }
                else
                    dp[i][j] = std::max(dp[i - 1][j], dp[i][j - 1]) + (str1[i] == str2[j]);
            }
        }
    }
};

class LcsReccursion : public ILcs
{
public:
    LcsReccursion(const std::string& str1, const std::string& str2)
        : str1 {str1}
        , str2 {str2}
        , dp {vvi(str1.size(), std::vector<int>(str2.size(), nil))}
    {}

    int lcs() override
    {
        return lcs(str1.size() - 1, str2.size() - 1);
    }

    int lcs(int i1, int i2) override
    {
        if (dp[i1][i2] != nil)
            return dp[i1][i2];

        if (i1 == 0 || i2 == 0)
        {
            if (i1 == 0 && i2 == 0) return dp[i1][i2] = (str1[i1] == str2[i2]);
            else if (i1 == 0)       return dp[i1][i2] = std::max(lcs(i1, i2 - 1), (str1[i1] == str2[i2] ? 1 : 0));
            else                    return dp[i1][i2] = std::max(lcs(i1 - 1, i2), (str1[i1] == str2[i2] ? 1 : 0));
        }

        dp[i1][i2] = std::max(lcs(i1 - 1, i2), lcs(i1, i2 - 1))
            + (str1[i1] == str2[i2]);
        return dp[i1][i2];
    }

private:

    std::string str1;
    std::string str2;
    vvi         dp;
};

void solve()
{
    using namespace std;

    int n;
    cin >> n;

    string s1, s2;

    for (int i = 0; i < n; ++i)
    {
        cin >> s1 >> s2;
        //LcsLoop lcs {s1, s2};
        LcsReccursion lcs {s1, s2};
        cout << lcs.lcs() << ((i != n - 1) ? "\n" : "");
    }
}

int main()
{
    solve();
    return 0;
}