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<algorithm>
#include<cctype>
#include<utility>
#include<string>
#include<cmath>
#include<cstring>
#include<queue>
#include<map>
#include<set>

#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 FORR(i, m, n) for(int i = m;i >= n;i--)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define llong long long
#define pb(a) push_back(a)

using namespace std;

typedef long long int ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;


template<typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
	return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}
template<typename T, typename V>
typename enable_if<is_class<T>::value == 0>::type
fill_v(T& t, const V& v) { t = v; }
template<typename T, typename V>
typename enable_if<is_class<T>::value != 0>::type
fill_v(T& t, const V& v) {
	for (auto& e : t) fill_v(e, v);
}


#define ARRAY_MAX 100005
const ll INF = 1e9 + 7;
const ll MOD = 1e9 + 7;

int dx[4] = { 1,0,0,-1 };
int dy[4] = { 0,1,-1,0 };


struct Combination {

	vector<ll> fact, rfact;

	Combination(ll sz) : fact(sz + 1), rfact(sz + 1) {

		fact[0] = 1;
		for (ll i = 1; i < fact.size(); i++) {
			fact[i] = fact[i - 1] * i % MOD;
		}
		//逆元
		rfact[sz] = inv(fact[sz]);
		for (ll i = sz - 1; i >= 0; i--) {
			rfact[i] = rfact[i + 1] * (i + 1) % MOD;
		}
	}

	ll inv(ll x) {
		//modpow
		return pow(x, MOD - 2);
	}
	ll pow(ll x, ll n) {
		//累乗
		ll ret = 1;
		while (n > 0) {
			if (n & 1) (ret *= x) %= MOD;
			(x *= x) %= MOD;
			n >>= 1;
		}
		return (ret);
	}
	ll P(ll n, ll r) {
		//順列
		if (r < 0 || n < r) return (0);
		return (fact[n] * rfact[n - r] % MOD);
	}

	ll C(ll p, ll q) {
		//組み合わせ
		if (q < 0 || p < q) return (0);
		return (fact[p] * rfact[q] % MOD * rfact[p - q] % MOD);
	}

	ll H(ll n, ll r) {
		//重複組み合わせ
		if (n < 0 || r < 0) return (0);
		return (r == 0 ? 1 : C(n + r - 1, r));
	}
};


/******************************************************************************************/


ll LCS(string& s, string& t) {


	auto dp = make_v<ll>(s.size() + 10, t.size() + 10);
	fill_v(dp, 0);

	for (ll i = 0; i < s.size(); i++) {
		for (ll 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]);
			}
		}
	}
	return dp[s.size()][t.size()];
}


int main() {

	int n;
	cin >> n;
	for (int _ = 0; _ < n; _++)
	{
		string s, t;
		cin >> s >> t;
		cout << LCS(s, t) << endl;
	}

	

	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

#define rep(i,x,y) for(ll i=(x);i<(y);i++)
#define rrep(i,x,y) for(ll i=(ll)(y)-1;i>=(x);i--)
#define all(x) (x).begin(),(x).end()
#ifdef LOCAL
#define dump(x)  cerr << #x << " = " << (x) << endl
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl
#define dassert(...) assert(__VA_ARGS__)
#else
#define dump(x)
#define debug(x)
#define dassert(...)
#endif
//#define int long long

typedef long long ll;
const ll MOD = 1e9 + 7;
const long double EPS = 1e-8;

signed main(){
    int q;
    cin >> q;
    rep(_,0,q) {
        string x, y;
        cin >> x >> y;
        vector<vector<int>> dp(x.size()+1, vector<int>(y.size()+1));
        rep(i,1,x.size()+1) {
            rep(j,1,y.size()+1) {
                dp[i][j] = ((x[i-1] == y[j-1]) ? (dp[i-1][j-1] + 1) : max(dp[i][j-1], dp[i-1][j]));
            }
        }
        cout << dp.back().back() << endl;
    }
}

C++: #include <cstdio>
#include <algorithm>
#include <iostream>
#include <cstring>
#include <memory>
#include <string>
#include <map>
using namespace std;
#define MAX 1003

char A[MAX];
char B[MAX];

void print(){}
int DP[MAX][MAX];
int dp(int i,int j){
    if(i<0||j<0) return 0;
    if(DP[i][j]!=-1) return DP[i][j];
    if(A[i]==B[j]) return DP[i][j]=dp(i-1,j-1)+1;
    return DP[i][j]=max(dp(i,j-1),dp(i-1,j));
}
void solve(){


    int tmp;
        scanf("%d",&tmp);
        int r,c;
        while(tmp--){

                scanf("%s%s",A,B);
                r=strlen(A);
                c=strlen(B);
                memset(DP,-1,sizeof(DP));
            printf("%d\n",dp(r-1,c-1));
        }

}

int main(){

    //freopen("in","r",stdin);
    solve();
    return 0;
}