Go: package main

/*
最長共通部分列
*/

import (
	"bufio"
	"bytes"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func larger(l, r int) int {
	if l > r {
		return l
	}
	return r
}

var memo [1001][1001]int

func countLCS(x, y string) int {
	x = " " + x
	y = " " + y
	max := 0
	for xi := 1; xi < len(x); xi++ {
		for yi := 1; yi < len(y); yi++ {
			if x[xi] == y[yi] {
				memo[xi][yi] = memo[xi-1][yi-1] + 1
			} else {
				memo[xi][yi] = larger(memo[xi-1][yi], memo[xi][yi-1])
			}
			max = larger(max, memo[xi][yi])
		}
	}
	return max
}

func main() {
	scanner := makeScanner(1024)
	q := eGetInt(scanner)
	for i := 0; i < q; i++ {
		x := eGetLine(scanner)
		y := eGetLine(scanner)
		fmt.Println(countLCS(x, y))
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}
func min(a []int) int {
	m := a[0]
	for _, v := range a {
		if v < m {
			m = v
		}
	}
	return m
}

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
#define len(n) (int)n.length()
#define pb push_back
#define ll long long
#define make_pair mkp
#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define ALL(v) (v).begin(), (v).end()
#ifdef DBGPRT
#define dbg(n) cerr << "//" << #n << ":" << n <<endl
#else
#define dbg(n) ;
#endif
typedef pair<ll, ll> LLARR;
#define INF 999999999
const double PI = 3.1415926535897932384626433832795;

int lcs(string s1, string s2)
{
	int m = len(s1);
	int n = len(s2);
	s1 = ' '+s1;
	s2 = ' '+s2;
	int (*mat)[1001];
	mat = new int[1001][1001];
	REP(i, m)
	{
		mat[i][0] = 0;
	}
	REP(i, n)
	{
		mat[0][i] = 0;
	}
	int maxx = 0;
	FOR(i, 1, m+1)
	{
		FOR(j, 1, n+1)
		{
			if (s1[i] == s2[j])
				mat[i][j] = mat[i-1][j-1] + 1;
			else
				mat[i][j] = max(mat[i][j-1], mat[i-1][j]);
			maxx = max(maxx, mat[i][j]);
		}
	}
	delete[] mat;
	return maxx;
}
int main()
{
	ios::sync_with_stdio(false);

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

C++: #include <iostream>
#include <string>
#define MAX 100001
#define SENTINEL 2000000000
using namespace std;

int solved[MAX];
int d[1001][1001];

void lcs(string a, string b)
{
    int m = a.size();
    int n = b.size();
    a = ' ' + a;
    b = ' ' + b;
    for (int i = 1; i <= m; i++)
    {
        d[i][0] = 0;
    }
    for (int i = 1; i <= n; i++)
    {
        d[0][i] = 0;
    }

    int max_lcs = 0;

    for (int i = 1; i <= m; i++)
    {
        for (int j = 1; j <= n; j++)
        {
            if (a[i] == b[j])
            {
                d[i][j] = d[i - 1][j - 1] + 1;
            }
            else
            {
                d[i][j] = max(d[i - 1][j], d[i][j - 1]);
            }
            max_lcs = max(max_lcs, d[i][j]);
        }
    }
    cout << max_lcs << endl;
}

int main()
{
    int q;
    cin >> q;
    for (int i = 0; i < q; i++)
    {
        string a, b;
        cin >> a >> b;
        lcs(a, b);
    }
    return 0;
}

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

#define MAX 1000

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

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

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 i,j;
  int maxl=0;
  X=' '+X;
  Y=' '+Y;
 
  for(i=1;i<=m;i++) c[i][0]=0;
  for(j=1;j<=n;j++) c[0]c[j]=0;

  for(i=1;i<=m;i++){
    for(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 <iostream>
#include <vector>

using namespace std;

#define debug(x) cout << #x << "==" << x << endl;

const int inf = 100000000;

typedef long long ll;


int lcs(string s, string t, int si, int ti) {
  
  if( si == -1 || ti == -1 ) {
    return 0;
  }

  int res = 0;

  if( s[si] == t[ti] ) {
    res = lcs(s, t, si-1, ti-1) + 1;
  } else {
    res = max( lcs(s, t, si-1, ti), lcs(s, t, si, ti-1) );
  }

  return res;

}

int solve() {

  string s, t;
  cin >> s >> t;

  return lcs(s, t, s.size()-1, t.size()-1);


  // dp[i][j] := s_1,...s_i と t_1,...t_j に対するLCSの長さ
  // s[i] == t[j] なら dp[i-1][j-1] + 1
  // s[i] != t[j] なら max( dp[i-1][j], dp[i][j-1] )
  // int dp[s.size()+1][t.size()+1];
  // fill(dp[0], dp[s.size()+1], 0);
  // for(int i = 0; i < s.size(); i++) {
  //   for(int j = 0; j < t.size(); j++) {
  //     if( s[i] == t[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[s.size()][t.size()];



}


int main() {
  ios::sync_with_stdio(false);

  int N;
  cin >> N;

  for(int i = 0; i < N; i++) {
    cout << solve() << "\n";
  }


  return 0;
}