Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	for i := 0; i < n; i++ {
		x := getNextString(scanner)
		y := getNextString(scanner)

		fmt.Fprintln(writer, lcs(x, y))
	}

	writer.Flush()
}

func lcs(x, y string) int {
	lx := len(x)
	ly := len(y)
	dp := make([][]int, lx+1)
	for i := 0; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
	}
	for i := 0; i < lx; i++ {
		for ii := 0; ii < ly; ii++ {
			if x[i] == y[ii] {
				dp[i+1][ii+1] = dp[i][ii] + 1
				continue
			}
			dp[i+1][ii+1] = dp[i][ii+1]
			if dp[i+1][ii] > dp[i+1][ii+1] {
				dp[i+1][ii+1] = dp[i+1][ii]
			}
		}
	}
	return dp[lx][ly]
}

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

class TLcsSolver
{
    int FTable[1000][1000];
    const char* FArray1;
    const char* FArray2;
    const int Fn1;
    const int Fn2;

    int Count(int i, int j)
    {
        if(i == 0 || j == 0) return 0;
        if(FArray1[i-1] == FArray2[j-1]){
            return FTable[i-1][j-1] + 1;
        }
        return std::max(FTable[i-1][j], FTable[i][j-1]);
    }
    void Solve()
    {
        for(std::size_t i = 1; i < Fn1; ++i){
            for(std::size_t j = 1; j < Fn2; ++j){
                FTable[i][j] = Count(i, j);
            }
        }
    }
public:
    TLcsSolver(const char* a, const char* b)
     : FArray1(a), FArray2(b)
     , Fn1(std::strlen(a)), Fn2(std::strlen(b))
    {
        Solve();
    }
    int Answer()const
    {
        return FTable[FArray1.size()][FArray2.size()];
    }
};

int main()
{
    int n;
    std::scanf("%d", &n);
    char a[1000];
    char b[1000];
    for(int i = 0; i < n; ++i){
        std::fgets(a, 1000, stdin);
        std::fgets(b, 1000, stdin);
        std::printf("%d", TLcsSolver(a, b).Answer());
    }
    return 0;
}

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

#define NUM 1000

string X;
string Y;
int dp[NUM + 1][NUM + 1];

void init(){
    for(int i = 0; i < NUM + 1; i++){
        for(int j = 0; j < NUM + 1; j++){
            dp[i][j] = 0;
        }
    }
}

void calc(void){
    init();

    for(int j = 1; j <= Y.size(); j++){
        for(int i = 1; i <= X.size(); i++){
            if(Y[j] == X[i]){
                dp[i][j] = dp[i - 1][j - 1] + 1;
            }else{
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
            }
        }
    }
    
    printf("%d\n", dp[X.size()][Y.size()]);

}

int main(void){
    int q;
    scanf("%d", &q);

    for(int i = 0; i < q; i++){
        cin >> X;
        cin >> Y;
        calc();
    }
}

C++: #include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
const int maxx=1010;

int main (){
	int dp[maxx][maxx];
	string s,p;
	int q;
	cin>>q;
	while(q--){
		cin>>s>>p;
		for(int i=1;i<=s.size();i++) dp[i][0]=0;
		for(int i=1;i<=p.size();i++) dp[0][i]=0;
		for(int i=0;i<=s.size();i++){
			for(int j=0;j<=p.size();j++){
				if(s[i]==p[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[s.size()][p.size()]-1<<endl;
	}
	return 0;
}

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


int main(int argc, char *argv[]){
  int n;
  cin >> n;
  for (int r = 0; r < n; r++) {

    string x, y;
    cin >> x >> y;
    string dp[y.length() + 1][x.length() + 1];

    for (int i = 0; i < y.length(); i++) {
      for (int j = 0; j < x.length(); j++) {
        if(y[i] == x[j]){
          dp[i + 1][j + 1] = dp[i][j] + y[i];
        }else{
          dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
        }
      }
    }
    int ans = 0;
    for (int i = 0; i < x.length(); i++) {
      ans = max(ans, (int)dp[y.length()][i].length());
    }
    std::cout << ans << std::endl;
  }
  return 0;
}

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

int q;
string x, y;
int memo[1000][1000];

void init(){
  for(int i = 0; i < x.size(); i++){
    for(int j = 0; j < y.size(); j++){
      memo[i][j] = -1;
    }
  }
}

int lcs(int xp, int yp){
  if(xp < 0 || yp < 0) return 0;
  if(memo[xp][yp] >= 0) return memo[xp][yp];

  if(x[xp] == y[yp]){
    return memo[xp][yp] = lcs(xp - 1, yp - 1) + 1;
  }else{
    return memo[xp][yp] = max(lcs(xp - 1, yp), lcs(xp, yp - 1));
  }
}

int main(void){
  cin >> q;
  for(int i = 0; i < q; i++){
    cin >> x >> y;
    init();
    cout << lcs(x.size() - 1, y.size() - 1) << endl;
  }
  return 0;
}

C++: #include<bits/stdc++.h>
#define MAX 1002
#define INF 100000000
using namespace std;

int c[MAX][MAX]={},F[MAX]={};

int fib(int n){
  if(n==0||n==1)return 1;
  if(F[n]!=0)return F[n];
  return F[n]=fib(n-1)+fib(n-2);
}

void matrixChain(int p[],int n){
    int l,i,k,j,q;
    for(i=1;i<=n;i++)c[i][i]=0;
    for(l=2;l<=n;l++){
        for(i=1;i<=n-l+1;i++){
            j=i+l-1;
            c[i][j]=INF;
            for(k=i;k<j;k++){
                q=c[i][k]+c[k+1][j]+p[i-1]*p[k]*p[j];
                c[i][j]=min(c[i][j],q);
            }
        }
    }
}

void LCSLength(char *x,char *y){
    int m,n,i,j;
    for(m=0;x[m]!='\0';m++);
    for(n=0;y[n]!='\0';n++);

    // cout<<m<<" "<<n<<endl;
    for(i=0;i<MAX;i++)for(j=0;j<MAX;j++)c[i][j]=0;
    for(i=1;i<=m;i++)c[i][0]=0;
    for(j=0;j<=n;j++)c[0][j]=0;
    for(i=1;i<=m;i++){
        for(j=1;j<=n;j++){
            if(x[i-1]==y[j-1])c[i][j]=c[i-1][j-1]+1;
            else if(c[i-1][j]>=c[i][j-1])c[i][j]=c[i-1][j];
            else c[i][j]=c[i][j-1];
        }
    }
    // for(i=0;i<=m;i++){
    //     for(j=0;j<=n;j++){
    //         cout<<c[i][j];
    //     }
    //     cout<<endl;
    // }
    cout<<c[m][n]<<endl;
}


int main(){
    int n,p[MAX],i,j,k,m,g,count=0;
    char x[MAX],y[MAX];
    cin>>n;
    for(i=0;i<n;i++){
        scanf("%s",x);
        scanf("%s",y);
        LCSLength(x,y);
    }
    
    // matrixChain(p,n);
}

C++: //#define		FILE_INPUT_DEFINE
#ifdef		FILE_INPUT_DEFINE
#include	<fstream>
#endif		// FILE_INPUT_DEFINE

#include	<iostream>
#include	<string>
#include	<algorithm>

using namespace std;

#define			MAX		1000
#define			ind(x)		((x) - 1)

int C[MAX + 1][MAX + 1];

int LCS(string &X, string &Y)
{
	int			Xlen = X.length();
	int			Ylen = Y.length();

	for (int i = 0; i <= Xlen; ++i)
	{
		C[i][0] = 0;
	}

	for (int i = 0; i <= Ylen; ++i)
	{
		C[0][i] = 0;
	}

	for (int i = 1; i <= Xlen; ++i)
	{
		for (int j = 1; j <= Ylen; ++j)
		{
			if (X[ind(i)] == Y[ind(j)])
			{
				C[i][j] = C[i - 1][j - 1] + 1;
			}
			else
			{
				C[i][j] = max(C[i - 1][j], C[i][j - 1]);
			}
		}
	}

	return (C[Xlen][Ylen]);
}

int main()
{
#ifdef		FILE_INPUT_DEFINE
	// input from txt
	std::ifstream in(R"(C:\Temp\input.txt)");
	std::cin.rdbuf(in.rdbuf());
#endif		// FILE_INPUT_DEFINE

	string	X, Y;
	int		n;

	cin >> n;
	cin.clear();
	cin.ignore();

	for (int i = 0; i < n; ++i)
	{
		getline(cin, X);
		getline(cin, Y);

		cout << LCS(X, Y) << endl;
	}

	return 0;
}