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++: #include <iostream>
#include <string>
#include <algorithm>
    using namespace std;
int lcs(string x,string y){
    int c[1010][1010];
    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(){
    int q;
    string x;
    string y;
    scanf("%d",&q);
    for (int i=0; i<q; i++) {
        cin>>x>>y;
        cout<<lcs(x, y)<<endl;
    }
    return 0;
}

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


int lcs(string x, string y){
  int m = x.size();
  int n = y.size();

  int c[1001][1001];
  for(int i=0;i<=m;i++) c[i][0] = 0;
  for(int j=0;j<=n;j++) c[0][j] = 0;

  int maxl = 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(){
  int q;
  cin >> q;
  string s1, s2;
  for(int i=0;i<q;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)
using namespace std;

static const int N = 1000;

int LCS(string x, string y) {
    int c[N + 1][N + 1];
    int n = x.length();
    int m = y.length();
    int maxl = 0;
    x = ' ' + x;
    y = ' ' + y;

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

    return maxl;
}

int soraLCS(string x, string y) {
    int n = x.length();
    int m = y.length();
    x = ' ' + x;
    y = ' ' + y;
    int c[N + 1][N + 1];
    REP(i, n) c[i][0] = 0;
    REP(i, m) c[0][i] = 0;

    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; 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]);
            }
        }
    }
    return c[n][m];
}

int main() {
    int q;
    string X, Y;

    cin >> q;
    REP(i, q) {
        cin >> X >> Y;
        cout << soraLCS(X, Y) << endl;
    }
    return 0;
}

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

using namespace std;
const int MAX_Q = 150, MAX_X = 1000;
int q, dp[MAX_X + 1][MAX_X + 1];
string x[MAX_X], y[MAX_X];

void solve() {
    for (int i = 0; i < q; i++) {
        for (int j = 0; j < x[i].length(); j++) {
            for (int k = 0; k < y[i].length(); k++) {
                if (x[i][j] == y[i][k]) {
                    dp[j + 1][k + 1] = dp[j][k] + 1;
                } else {
                    dp[j + 1][k + 1] = max(dp[j][k + 1], dp[j + 1][k]);
                }
            }
        }
        cout << dp[x[i].length()][y[i].length()] << endl;
    }
}

int main() {
    cin >> q;
    for (int i = 0; i < q; i++) {
        cin >> x[i] >> y[i];
    }
    solve();
    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 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++: //Longest Common Subsequence
#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
#define REP(i, limit) for(int i=0; i< limit; ++i)
#define LINT long long

int main(){
  int q;
  string X, Y;
  int dp[1001][1001]={};
  int m, n;
  int ans;


  cin >> q;
  REP(s, q){
    dp[1001][1001]={};
    cin >> X >> Y;
    m=X.size();
    n=Y.size();
    REP(i, m){
      REP(j, n){
        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]);
      }
    }
    cout << dp[m][n] <<endl;
  }


  return 0;
}

C++: #include<iostream>
using namespace std;
int lcs(string a,string b)
{
    if(a.length()<=0||b.length()<=0)
    {
        return 0;
    }
    else if(a[a.length()-1]==b[b.length()-1])
    {
        return 1+lcs(a.substr(0,a.length()-1),b.substr(0,b.length()-1));
    }
    else
    {
        return max(lcs(a.substr(0,a.length()),b.substr(0,b.length()-1)),lcs(a.substr(0,a.length()-1),b.substr(0,b.length())));
    }
};
int main()
{
    int num;
    cin>>num;
    for(int i=0;i<num;i++)
    {
        string a,b;
        cin>>a>>b;
        cout<<lcs(a,b)<<endl;
    }
}