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 <bits/stdc++.h>
using namespace std;
template<typename T>
ostream& operator<<(ostream& os, const vector<T>& v){
  const char* delimiter = "";
  for(const auto& x:v) cout << exchange(delimiter, ",") << x;
  return os;
}
// ALDS1_10_C: 最長共通部分列 (LCS)
int32_t main(){
  size_t q; cin>>q;
  for(size_t p=0; p<q; ++p){
    string s,t; cin>>s>>t;
    vector<vector<size_t>> dp(s.size()+1,vector<size_t>(t.size()+1));
    // i=0
    for(auto&& x:dp[0]) x=0;
    for(size_t i=1; i<dp.size(); ++i){
      // j=0
      dp[i][0]=0;
      for(size_t j=1; j<dp[i].size(); ++j){
        dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
        if(s[i-1]==t[j-1]) dp[i][j]=max(dp[i][j],dp[i-1][j-1]+1);
      }
    }
    cout<<dp.back().back()<<endl;
  }
}

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

#define MAX 1000

int c[MAX+1][MAX+1];

int lcs(string A, string B)  {
    int a = A.length();
    int b = B.length();
    int maxl = 0;

    A = ' ' + A;
    B = ' ' + B;
    //配列を作る
    for(int i=0; i<a; i++) {
        c[i][0] = 0;
    }
    for(int j=0; j<b; j++) {
        c[0][j] = 0;
    }
    for(int i=1; i<=a; i++) {
        for(int j=1; j<=b; j++) {
            if(A[i]==B[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<algorithm>
#include<cstdio>
#include<cmath>
#include<cctype>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define MOD 1000000007
#define rep(i,n) for(i=0;i<(n);i++)
#define loop(i,a,n) for(i=a;i<(n);i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int,int> pii;

int main(void) {
  int i,j;
  int q;
  cin>>q;

  while(q--){
    string s,t;
    cin >> s >> t;
    int n = s.size();
    int m = t.size();

    vector<vi> dp(n+1,vi(m+1,0));

    loop(i,1,n+1)loop(j,1,m+1){
      if(s[i-1] == t[j-1]){
        dp[i][j] = dp[i-1][j-1] + 1;
      }else{
        dp[i][j] = max(dp[i][j-1], dp[i-1][j]);
      }
    }

    cout << dp[n][m] << endl;
  }
}

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

#define N 1000

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

    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;
}

using namespace std;

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

C++: #include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>

using namespace std;

static const int N = 1000;

int c[N + 1][N + 1];
int lcs(string s1, string s2){
	int m = s1.size();
	int n = s2.size();
	int maxL = 0;

	s1 = ' ' + s1;
	s2 = ' ' + s2;
	for (int i = 1; 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 (s1[i] == s2[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 <cstring> 
using namespace std;
int c[1001][1001];

int lcs(string x, string y)
{
    int maxl = 0;
    int m = x.length(), n = y.length();
 
    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-1] == y[j-1])
            { 
                // if(i==0 || j==0) c[i][j] = 1;
                c[i][j] = c[i-1][j-1] + 1; 
            }else
            {
                // if(i==0 || j==0) c[i][j] = 0;
                c[i][j] = max(c[i][j-1], c[i-1][j]);
            }
            maxl = max(maxl, c[i][j]);
        } 
    } 
    // printf("%d\n", c[m][n]);
    return c[m][n];
}

int main()
{
    string x,y;
    int q;
    cin>>q;
    while(q--)
    {
        cin>>x>>y;
        int ans = lcs(x, y);
        cout<<ans<<endl;
    }
    return 0;
}