Go: package main

import (
	"fmt"
)

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

	for i := 0; i < q; i++ {
		var x, y string
		fmt.Scan(&x)
		fmt.Scan(&y)

		xs := []rune(x)
		ys := []rune(y)

		xn := len(xs)
		yn := len(ys)
		dp := make([][]int, xn+1)
		for j := 0; j <= xn; j++ {
			dp[j] = make([]int, yn+1)
		}

		for j := 1; j <= xn; j++ {
			for k := 1; k <= yn; k++ {
				dp[j][k] = max(dp[j-1][k], dp[j][k-1])
				if xs[j-1] == ys[k-1] {
					dp[j][k] = max(dp[j][k], dp[j-1][k-1] + 1)
				} else {
					dp[j][k] = max(dp[j][k], dp[j-1][k-1])
				}
			}
		}
		fmt.Println(dp[xn][yn])
	}
}

func max(a, b int) int {
	if a < b {
		return b
	} else {
		return a
	}
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main()
{
    int n;
    cin >> n;
    rep(k, n) {
        string x, y;
        cin >> x >> y;
        vector<vector<int>> dp(x.size(), vector<int>(y.size(), 0));
        int d;
        d = 0;
        for (int i = 0; i < x.size(); i++) {
            if (x[i] == y[0]) d = 1;
            dp[i][0] = d;
        }
        d = 0;
        for (int j = 0; j < y.size(); j++) {
            if (y[j] == x[0]) d = 1;
            dp[0][j] = d;
        }
        for (int i = 1; i < x.size(); i++) {
            for (int j = 1; j < y.size(); j++) {
                if (x[i] == y[j]) {
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                } else {
                    dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
                }
            }
        }
        cout << dp[x.size() - 1][y.size() - 1] << endl;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
int dp[1001][1001];

int solve(string s1,string s2){
	int m=s1.size() ;
	int n=s2.size() ;
	s1=' '+s1;
	s2=' '+s2;
	memset(dp,0,sizeof(dp));
	int maxl=0;
	for(int i=1;i<=m;i++){
		for(int j=1;j<=n;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]);
			}
			maxl=max(maxl,dp[i][j]);
		}
	}
	return maxl;
}

int main(){
	int t;
	cin>>t;
	while(t--){
		string s1,s2;
		cin>>s1>>s2;
		cout<<solve(s1,s2)<<endl;
	}
}

C++: #include<iostream>
#include<string>
using namespace std;

#define MAX 150
#define MAXL 1000

int C[MAXL+1][MAXL+1];

int lec(string X,string Y)
{
    int XL = X.length();
    int YL = Y.length();
    for(int i=0;i<=XL;i++)
        C[i][0] = 0;
    for(int i=0;i<=YL;i++)
        C[0][i] = 0;
    for(int i=0;i<=XL;i++)
    {
        for(int j=0;j<=YL;j++)
        {
            if(X[i+1]==Y[j+1])
            {
                C[i+1][j+1] = C[i][j]+1;
            }
            else if(C[i][j+1] > C [i+1][j])
            {
                C[i+1][j+1] = C[i][j+1];
            }else{
                C[i+1][j+1] = C[i+1][j];
            }
        }
    }
    return C[XL][YL];
}

int main()
{
    int q;
    string x,y;
    cin>>q;
    for(int i=0;i<q;i++)
    {
        cin>>x>>y;
        cout<<lec(x,y)<<endl;
    }
    return 0;
}

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

using namespace std;

typedef long long ll;

int lcs(string X, string Y){
  int x = X.size();
  int y = Y.size();

  int d[y+1][x+1];
  memset(d, 0, sizeof(d));

  for(int i = 1; i <= y; i++){
    char a = Y[i];

    for(int j = 1; j <= x; j++){
      char b = X[j];

      if(a == b){
        d[i][j] = max(d[i][j], d[i-1][j-1] + 1);
      }else{
        d[i][j] = max(d[i][j], max(d[i-1][j], d[i][j-1]));
      }
    }
  }

  return d[y][x];
}

int main(){
  int n;
  string x, y;
  cin >> n;

  for(int i = 0; i < n; i++){
    cin >> x;
    cin >> y;

    cout << lcs(x, y) << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <math.h>
#include <cmath>
#include <vector>
using namespace std;

int q;
string strs[310];
int memo[1010][1010];

void initMemo(int l1, int l2) {
    for (int i = 0; i <= l1; i++) {
        memo[0][i] = 0;
    }

    for (int i = 0; i <= l2; i++) {
        memo[i][0] = 0;
    }
}

void store() {
    cin >> q;
    for (int i = 0; i < 2 * q; i++) {
        cin >> strs[i];
    }
}

// Longest Common Subsequence
void LCS(string s1, string s2) {
    int l1 = s1.length();
    int l2 = s2.length();
    initMemo(l1, l2);

    for (int i = 1; i <= l1; i++) {
        for (int j = 1; j <= l2; j++) {
            if (s1[i - 1] == s2[j - 1]) {
                memo[i][j] = memo[i - 1][j - 1] + 1;
            } else {
                memo[i][j] = max(memo[i - 1][j], memo[i][j - 1]);
            }            
        }
    }

    cout << memo[l1][l2] << endl;
}

void AllLCS() {
    for (int i = 0; i < 2 * q; i += 2) {
        LCS(strs[i], strs[i + 1]);
    }
}


int main() {
    store();
    AllLCS();

    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() + 1, std::vector<int>(str2.size() + 1))}
    {
        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)
            dp[i][0] = 0;
        for (int i = 0; i < str2.size(); ++i)
            dp[0][i] = 0;

        for (int i = 1; i < str1.size(); ++i)
        {
            for (int j = 1; j < str2.size(); ++j)
            {
                if (str1[i] == str2[j])
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                else
                    dp[i][j] = std::max(dp[i][j - 1], dp[i - 1][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;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
int dp[1001][1001];
string s,t;
int n,m,a,ans;
int main(){
  cin>>a;
  for(int b=0;b<a;b++){
    cin>>s>>t;
    for(int i=0;i<=1000;i++)
      for(int j=0;j<=1000;j++)
	dp[i][j]=0;
    m=s.size();
    n=t.size();
    ans=0;
    for(int i=1;i<=m;i++){
      for(int j=1;j<=n;j++){
	if(s[i-1]==t[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[m][n]<<endl;
  }
  return 0;
}