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;
typedef  long long ll;
using vll=vector<ll>;
using vi=vector<int>;
using vb=vector<bool>;
using pii=pair<int,int>;

template<class T> inline bool chmin(T& a, T b) {if (a > b) {a = b;return true;}return false;}
template<class T> inline bool chmax(T& a, T b) {if (a < b) {a = b;return true;}return false;}

//pow(llpow,modpow)
template<class T> ll llpow(ll x,T n){ll ans=1;if(x==0)ans=0;while(n){if(n&1)ans*=x;x*=x;n>>=1;}return ans;}
long long modpow(long long a, long long n, long long mod) {long long res = 1;while (n > 0) {if (n & 1) res = res * a % mod;a = a * a % mod;n >>= 1;}return res;}
//最大公約数
template<class T> inline T gcd(T x,T y){if(y==0)return x; else {return gcd(y,x%y);}}
//最小公倍数
template<class T> inline T lcm(T x,T y){return x/gcd(x,y)*y;}
//逆元
long long modinv(long long a, long long m) {long long b = m, u = 1, v = 0;while (b) {long long t = a / b;a -= t * b; swap(a, b);u -= t * v; swap(u, v);}u %= m;if (u < 0) u += m;return u;}

#define rep(i, begin_i, end_i) for (ll i = (ll)begin_i; i < (ll)end_i; i++)

long long INF = 1LL<<60;
int main( ){
    int Q;
    cin>>Q; ;
    rep(c,0,Q){
        string X,Y;
        cin>>X>>Y;
        int xs=X.size()+1;
        int ys=Y.size()+1;
        int dp[xs][ys];
        rep(i,0,xs)dp[i][0]=0;
        rep(j,0,ys)dp[0][j]=0;

        rep(i,1,xs){
            rep(j,1,ys){
                if(X[i-1]==Y[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[xs-1][ys-1]<<endl;
    }
    return 0;
}

C++: #include<iostream>
#include<math.h>
#include<algorithm>
#include<stdint.h>
#include<vector>
#include<deque>
#include<stack>
#include<string>
#include<cstring>
#include<time.h>
#include<iomanip>
#include<list>
#include<set>
#include<unordered_map>
#include<unordered_set>
#include<random>
#include<bitset>
#include <queue>
#include <map>


using namespace std;
using ll = long long;
using ull = unsigned long long;
using uint = unsigned int;
using ldouble = long double;


#define repi(i,a,b) for(ll i = (a); i < (b); i++)
#define rep(i, n) for(ll i = 0; i < (n); ++i)


ll MOD = 1000000007;


int f(string x, string y) {
	vector<vector<int>> dp(x.size() + 1);
	rep(i, x.size() + 1) {
		dp[i].resize(y.size() + 1);
		rep(j, y.size() + 1) dp[i][j] = 0;
	}
	repi(i, 1, x.size() + 1) {
		repi(j, 1, y.size() + 1) {
			if (x[i - 1] == y[j - 1]) {
				dp[i][j] = dp[i-1][j-1] + 1;
			}
			else {
				dp[i][j] = max(dp[i][j - 1], max(dp[i - 1][j], dp[i - 1][j - 1]));
			}
		}
	}
	return dp.back().back();
}


int main() {
	int N;
	cin >> N;
	vector<pair<string, string>> s;
	rep(i,N){
		string a, b;
		cin >> a >> b;
		s.push_back(pair<string, string>(a, b));
	}
	rep(i, N) cout << f(s[i].first, s[i].second) << endl;
	return 0;
}

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

#define REP(i, n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()
const int INF = 1e9;

using namespace std;
int dp[1000][1001] = {0};

void dfs(int i, int j, string q, string b){
    int x = j;
    string tar = b.substr(x, 1);
    while(x < b.length() && q != tar){
        x++;
        tar = b.substr(x, 1);
    }
    if(i == 0 && x < b.length()){
        while(x < b.length()){
            x++;
            dp[i][x] = 1;
        }
        return;
    }
    while(x < b.length()){
        x++;
        dp[i][x] = max(dp[i-1][j] + 1, dp[i][x]);
    }
    dp[i][j] = max(dp[i][j], dp[i-1][j]);
    return;
}

int main() {
    int n; cin >> n;
    REP(k, n){
        REP(i, 1000) REP(j, 1001) dp[i][j] = 0;
        string a, b;
        cin >> a >> b;
        REP(i, a.length()){
            string q = a.substr(i, 1);
            REP(j, b.length()+1) dfs(i, j, q, b);
        }
        cout << dp[a.length()-1][b.length()] << endl;
    }
    return 0;
}

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