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<vector>
#include<limits.h>
#include<string>
using namespace std;

int LCS(string a, string b){
	int n=a.size();
	int m=b.size();
	int T[n+1][m+1];
	int i,j;
	for (i=0;i<n+1;i++) T[i][0]=i;
	for (j=0;j<m+1;j++) T[0][j]=j;
	for (i=1;i<n+1;i++){
		for (j=1;j<m+1;j++){
			int min=T[i-1][j]+1;
			if (min>T[i][j-1]+1){
				min=T[i][j-1]+1;
			}
			if ((a[i-1]==b[j-1])&&(min>T[i-1][j-1]+1)){
				min=T[i-1][j-1]+1;
			}
			T[i][j]=min;
		}
	}
	return n+m-T[n][m];
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n,i;
	cin >> n;
	
	string a,b;
	for (i=0;i<n;i++){
		cin >> a >> b;
		cout << LCS(a,b) << endl;
	}
	return 0;
}

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

void solve(){
    string S, T;
    cin >> S;
    cin >> T;

    int dp[1001][1001];
    dp[0][0] = 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+1][j], dp[i][j+1]);
        }
    }
    cout << dp[S.size()][T.size()] << endl;
}

int main(){
    int q;
    cin >> q;

    for (int i = 0; i < q; i++)
        solve();
}

C++: #include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef vector<ld> vd;
typedef vector<ll> vll;
typedef vector<string> vstr;
typedef vector<vector<ll>> vvll;
typedef vector<pair<ll, ll>> vpll;
typedef priority_queue<ll, vector<ll>, greater<ll>> spqll;  // 小さい順に取り出し
typedef priority_queue<ll, vector<ll>, less<ll>> bpqll;     // 大きい順に取り出し

#define REP(i, n) for (ll i = 0; i < (ll)(n); i++)
#define FOR(i, a, b) for (ll i = (ll)a; i < (ll)b; i++)
#define IREP(i, v) for (auto i = (v).begin(); i != (v).end(); i++)
#define FI first
#define SE second
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define TS to_string
#define NP next_permutation
#define ALL(v) (v).begin(), (v).end()
#define SZ(x) (ll) x.size()
#define SP(x) setprecision((ll)x)


ll INF = 1e9;
ll NIL = -1;
ll MOD = 1000000007;
ll LINF = 1e18;
ld EPS = 1e-9;
ld PI = M_PI;
vll dx = {1, 0, -1, 0, 1, -1, -1, 1};
vll dy = {0, 1, 0, -1, 1, 1, -1, -1};
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a;} //最大公約数
ll lcm(ll a, ll b) { return a / gcd(a, b) * b;}     //最小公倍数

void yes(){ cout << "yes" << endl;}
void no(){ cout << "no" << endl;}

//-----------------------------------------
int dp[1000+10][1000+10];



//-----------------------------------------
int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n;
  cin >> n;
  for(int i=0;i<n;i++){
    string s, t;
    cin >> s >> t;
    int ss = s.size();
    int st = t.size();
    for(int i=0;i<=ss;i++){
      for(int j=0;j<=st;j++){
        if(i==0 || j==0) dp[i][j] = 0;
        else dp[i][j] = -1;
      }
    }
    for(int i=1;i<=ss;i++){
      for(int j=1;j<=st;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[ss][st] <<endl;
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
 
#define rep(i, n) for (int i = (int)(0); i < (int)(n); ++i)
#define reps(i, n) for (int i = (int)(1); i <= (int)(n); ++i)
#define rrep(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
#define rreps(i, n) for (int i = ((int)(n)); i > 0; i--)
#define irep(i, m, n) for (int i = (int)(m); i < (int)(n); ++i)
#define ireps(i, m, n) for (int i = (int)(m); i <= (int)(n); ++i)
#define FOR(e, c) for (auto &e : c)
#define SORT(v, n) sort(v, v + n);
#define vsort(v) sort(v.begin(), v.end());
#define rvisort(v) sort(v.begin(), v.end(), greater<int>());
#define all(v) v.begin(), v.end()
#define mp(n, m) make_pair(n, m);
#define cout(d) cout<<d<<endl;
#define coutd(d) cout<<std::setprecision(10)<<d<<endl;
#define cinline(n) getline(cin,n);
#define replace_all(s, b, a) replace(s.begin(),s.end(), b, a);
#define rv(s) reverse(s.begin(),s.end());
 
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using pii = pair<int, int>;
using vpii = vector<pii>;
using vs = vector<string>;
using vd = vector<double>;
using ul = unsigned long;
 
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

int GCD(int a, int b) { return b ? GCD(b, a%b) : a; }

int main()
{
  cin.tie( 0 );
  ios::sync_with_stdio( false );
  
  int q;cin>>q;
  
  rep(ki,q){
    string x,y;
    cin>>x>>y;
    int m=x.size();
    int n=y.size();
    int dp[1001][1001];
    
    rep(i,m)dp[i][0]=0;
    rep(i,n)dp[0][i]=0;
    
    for(int i=1;i<=m;i++){
      for(int j=1;j<=n;j++){
        if(x[i-1]==y[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]);
  }
}