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;
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 = 0; i < m; i++) c[i][0] = 0;
	for (int j = 0; 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][j - 1], c[i - 1][j]);
			}
		}
	}
	maxl = c[m][n];
	return maxl;
}

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

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


int main() {
    int q;
    cin>>q;
    
    while(1){
        //cout<<q<<endl;
        if(!q)break;
        string x,y;
        cin>>x>>y;
        int n=x.size();
        int m=y.size();
        int dp[1050][1050];
        for(int i=1;i<=m;i++){
            rep(j,n+1){
               dp[j][i]=0;
            }
        }
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(x[i]==y[j]){
                    dp[i+1][j+1] =  dp[i][j] + 1;
                }
                else{
                    dp[i+1][j+1]=max(dp[i+1][j],dp[i][j+1]);
                }
            }
        }cout<<dp[n][m]<<endl;
        q--;
    }
    
    
    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 k=0;k<a;k++){
    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;
}

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

int lcs(string x, string y) {
	int m = x.size();
	int n = y.size();
	//cout<<m<<n<<endl;
	int maxl = 0;
	int A[1001][1001]={};
	x = ' ' + x;
	y = ' ' + y;
//	cout<<x<<y;
	for (int i = 0;i <= m;i++) {
		A[i][0] = 0;
	}
	for (int j = 0;j <= n;j++) {
		A[0][j] = 0;
	}

	for (int i = 1;i <= m;i++) {
		for (int j = 1;j <= n;j++) {
		//	cout<<x[i]<<y[j]<<endl;
			if (x[i] == y[j]) {
					A[i][j] = A[i-1][j-1] + 1;
			}
	     	else {
					A[i][j] = max(A[i - 1][j], A[i][j - 1]);
			}

			maxl = max(maxl, A[i][j]);
		}
		
	}
	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;
		//lcs(x,y);

	}
	return 0;
}

C++: #ifdef LOCAL_BUILD
#include "pch.h"
#define DLOG(msg) cout << "#" << __LINE__ << ":" << msg << endl;
#define DLOG_V(var)\
  cout << "#" << __LINE__ << ":" << #var << " : " << var << endl;
#else
#include <bits/stdc++.h>
#define DLOG(msg)
#define DLOG_V(var)
#endif
using namespace std;

constexpr auto no_value = numeric_limits<uint64_t>::max();

int solve(const string& str1, const string& str2) {
  int max_ = 0;
  vector<vector<int>> buf(str1.size(), vector<int>(str2.size(), 0));
  for (size_t j = 0; j < str2.size(); ++j) {
    for (size_t i = 0; i < str1.size(); ++i) {
      auto prev1 = j == 0 ? 0 : buf[i][j - 1];
      auto prev2 = i == 0 ? 0 : buf[i - 1][j];
      buf[i][j] = max(prev1, prev2);
      if (str1[i] == str2[j]) {
        auto p = i == 0 || j == 0 ? 0 : buf[i - 1][j - 1];
        buf[i][j] = max(buf[i][j], p + 1);
        max_ = max(max_, buf[i][j]);
      }
    }
  }
  return max_;
}

int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; ++i) {
    string str1;
    string str2;
    cin >> str1 >> str2;
    auto res = solve(str1, str2);
    cout << res << endl;
  }
}

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

int lcs(string s,string t)
{
  int c[1005][1005];
  int m=s.size(),n=t.size(),len=0;

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


  for(int i=1;i<=m;i++)
  {
    for(int j=1;j<=n;j++)
    {
      if(s.at(i-1)==t.at(j-1)) c[i][j]=c[i-1][j-1]+1;
      else c[i][j]=max(c[i-1][j],c[i][j-1]);

      len=max(len,c[i][j]);
    }
  }

  return len;
}

int main()
{
  int q;
  cin>>q;
  string s,t;
  for(int i=0;i<q;i++)
  {
    cin>>s>>t;
    cout<<lcs(s,t)<<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 LMAX=0;
  int m=X.size(), n=Y.size();

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

  for(int i=0; i<=m; i++) c[i][0]=0;
  for(int j=0; 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]);
      }
      LMAX=max(LMAX, c[i][j]);
    }
  }

  return LMAX;
}

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;
}