Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

type Position struct {
	X int
	Y int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}
	for i := 0; i < n; i++ {
		strX := nextText(sc)
		strY := nextText(sc)
		fmt.Println(calcLcs(strX, strY))
	}
}

func calcLcs(strX, strY string) int {
	return lcs(strX, strY, Position{0, 0}, make(map[Position]int))
}

func lcs(strX string, strY string, position Position, memo map[Position]int) int {
	if position.X >= len(strX) || position.Y >= len(strY) {
		return 0
	}
	if v, ok := memo[position]; ok {
		return v
	}
	if strX[position.X] == strY[position.Y] {
		result := lcs(strX, strY, Position{position.X + 1, position.Y + 1}, memo)
		memo[position] = result + 1
		return memo[position]
	} else {
		result1 := lcs(strX, strY, Position{position.X + 1, position.Y}, memo)
		result2 := lcs(strX, strY, Position{position.X, position.Y + 1}, memo)
		var result int
		if result1 > result2 {
			result = result1
		} else {
			result = result2
		}
		memo[position] = result
		return result
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include <iostream>
#include <string>
using namespace std;
int main(void){
    int n;
    cin >> n;
    for(int i = 0;i < n;i++){
        string X,Y;
        cin >> X >> Y;
        int L[X.length()+10][Y.length()+10];
        for(int j = 0;j < X.length()+10;j++){
            for(int k = 0;k < X.length()+10;k++){
                L[j][k] = 0;
            }
        }
        for(int j = 1;j<=X.length();j++){
            for(int k = 1;k<=Y.length();k++){
                if(Y[k] == X[j]){
                    L[j][k] = 1+L[j-1][k-1];
                }
                else{
                    L[j][k] = max(L[j-1][k],L[j][k-1]);
                }
            }
        }
        cout << L[X.length()][Y.length()] << endl;
    }
return 0;
}

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

int dp[1001][1001];

int lcs(string x, string y)
{
	fill(dp[0], dp[0] + x.length() * y.length(), 0);
	for (int i = 0; i < x.length(); ++i)
	{
		for (int j = 0; j < y.length(); ++j)
		{
			if (x[i] == y[j])dp[i + 1][j + 1] = dp[i][j] + 1;
			else dp[i + 1][j + 1] = max(dp[i][j + 1], dp[i + 1][j]);
		}
	}
	return dp[x.length()][y.length()];
}

int main()
{
	string s1, s2;
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i)
	{
		cin >> s1 >> s2;
		cout << lcs(s1, s2) << endl;
	}
	return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS

#include<iostream>
#include<functional>
#include<algorithm>
#include<stack>
#include<queue>
#include<iomanip>
#include<set>
#include<map>
#include<utility>
#include<string>
#include<vector>

using namespace std;

#define LL long long

string X,Y;
int q,Z;
int dp[1001][1001]={};

int main() {
	cin>>q;
	for(int ds=0;ds<q;ds++){
		cin>>X>>Y;
		int xs=X.size(),ys=Y.size();
		for(int i=0;i<xs;i++){
			for(int j=0;j<ys;j++){
				int tmp=0;
				if(X[i]==Y[j]){
					if(i*j==0)dp[i][j]=1;
					else dp[i][j]=dp[i-1][j-1]+1;
				}
				else {
					if(i+j==0)dp[0][0]=0;
					else if(i==0)dp[0][j]=dp[0][j-1];
					else if(j==0)dp[i][0]=dp[i-1][0];
					else dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
				}
			}
		}
		cout<<dp[xs-1][ys-1]<<endl;
	}
	return 0;
}

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

int lcs(string X, string Y)
{
	static int Z[1001][1001];
	int m = X.size();
	int n = Y.size();
	int i, j;

	for (i = 1; i <= m; i++) {
		for (j = 1; j <= n; j++) {
			if (X[i - 1] == Y[j - 1])
				Z[i][j] = Z[i - 1][j - 1] + 1;
			else
				Z[i][j] = max(Z[i - 1][j], Z[i][j - 1]);
		}
	}
	return Z[m][n];
}

int main()
{
	string X, Y;
	int q;
	scanf("%d", &q);
	for (int i = 0; i < q; i++) {
		cin >> X >> Y;
		cout << lcs(X, Y) << endl;
	}
	return 0;
}

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

static const int N = 1000;
int c[N+1][N+1];

int lcs(std::string X, std::string Y) {
    int m = X.size();
    int n = Y.size();
    for(int i = 0; i <= m; i++) {
        for(int j = 0; j <= n; j++) {
            c[i][j] = 0;
        }
    }

    X = ' ' + X;
    Y = ' ' + Y;

    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]= std::max(c[i-1][j], c[i][j-1]);
            }
        }
    }
    return c[m][n];
}

int main() {
    std::string s1, s2;
    int n; std::cin >> n;
    for(int i = 0; i < n; i++) {
        std::cin >> s1 >> s2;
        std::cout << lcs(s1, s2) << std::endl;
    }
    return 0;
}

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

void solve(string, string);
int main(){
  int q; cin >> q;

  for(int i=0; i<q; i++){
    string s, t;  cin >> s >> t;
    solve(s, t);
  }

  return 0;
}

void solve(string s, string t){
  int m=s.length(), n=t.length();
  s = " " + s; t = " " + t;

  int dp[m+1][n+1];
  for(int i=0; i<=m; i++) dp[i][0]=0;
  for(int i=0; i<=n; i++) dp[0][i]=0;

  for(int i=1; i<=m; i++){
    for(int j=1; j<=n; j++){
      if(s[i]==t[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[m][n] << endl;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
static const int N = 1000;

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

	return maxl;
}

int main() {
	string s1, s2;
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> s1 >> s2;
		cout << lcs(s1, s2) << endl;
	}

	return 0;
}

C++: #include<bits/stdc++.h>

#define rep(i,n) for(int i = 0; i < (n); i++)
#define rrep(i,n) for(int i = (n)-1; i >= 0; i--)
#define rep1(i,n) for(int i = 1; i <= (n); i++)
#define rrep1(i,n) for(int i = (n); i > 0; i--)

#define ll long long
#define pi pair<int, int>
#define pll pair<ll, ll>

#define MOD 1000000007
#define INF 1000000000000000LL

using namespace std;

#define MAXLEN 1001
int dp[MAXLEN][MAXLEN];

int main(){
  int n;cin>>n;
  rep(i, n){
    rep(i, MAXLEN)rep(j, MAXLEN)dp[i][j]=0;

    string l,r;cin>>l>>r;
    rep(x, l.size())rep(y, r.size()){
      if(l[x]==r[y]) dp[x+1][y+1] = dp[x][y]+1;
      else dp[x+1][y+1] = max(dp[x+1][y], dp[x][y+1]);

    // cout<<r[x]<<' '<<l[y]<<endl;
    // rep(x, l.size()+1){
    //   rep(y, r.size()+1)cout<<dp[x][y]<<' ';cout<<endl;
    // }
    // cout<<"#######"<<endl;

    }

    cout<<dp[l.size()][r.size()]<<endl;

  }
  return 0;
}