Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

type Position struct {
	X int
	Y int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}
	for i := 0; i < n; i++ {
		strX := nextText(sc)
		strY := nextText(sc)
		fmt.Println(calcLcs(strX, strY))
	}
}

func calcLcs(strX, strY string) int {
	return lcs(strX, strY, Position{0, 0}, make(map[Position]int))
}

func lcs(strX string, strY string, position Position, memo map[Position]int) int {
	if position.X >= len(strX) || position.Y >= len(strY) {
		return 0
	}
	if v, ok := memo[position]; ok {
		return v
	}
	if strX[position.X] == strY[position.Y] {
		result := lcs(strX, strY, Position{position.X + 1, position.Y + 1}, memo)
		memo[position] = result + 1
		return memo[position]
	} else {
		result1 := lcs(strX, strY, Position{position.X + 1, position.Y}, memo)
		result2 := lcs(strX, strY, Position{position.X, position.Y + 1}, memo)
		var result int
		if result1 > result2 {
			result = result1
		} else {
			result = result2
		}
		memo[position] = result
		return result
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

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

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

#define ull unsigned long long
#define ld long double

template <class T>
using V = vector<T>;
template <class T>
using VV = V<V<T>>;
template <class T>
using VVV = V<V<V<T>>>;

#define rep2(i, a, b) for (int i = (a); i < (b); ++i)
#define rep(i, n) rep2(i, 0, n)
#define rep1(i, n) rep1(i, 1, n + 1)

// #define repr(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
// #define rep1r(i, n) for (int i = ((int)(n)); i >= 1; i--)

#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()  //

#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define RSORT(x) sort(rall(x));

#define INF (1e9)
#define PI (acos(-1))
#define EPS (1e-7)

// 総数を1000000007（素数）で割った余り
const long long mod = 1e9 + 7;

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

ull gcd(ull a, ull b) { return b ? gcd(b, a % b) : a; }
ull lcm(ull a, ull b) { return a / gcd(a, b) * b; }

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << std::fixed << std::setprecision(15);
    //    cout << std::setfill('0') << std::setw(2);

    int Q;
    cin >> Q;
    rep(q, Q) {
        string S, T;
        cin >> S >> T;
        int s = S.size(), t = T.size();
        VV<int> dp(s + 1, V<int>(t + 1, 0));
        dp[0][0] = 0;
        rep(i, s) dp[i][0] = 0;
        rep(i, t) dp[0][i] = 0;

        rep2(i, 1, s + 1) rep2(j, 1, t + 1) {
            dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
            if (S[i - 1] == T[j - 1]) dp[i][j] = dp[i - 1][j - 1] + 1;
        }
        cout << dp[s][t] << endl;
    }

    return 0;
}

C++: #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#define MAX_L (1010)
using namespace std;

int q;
int dp[2][MAX_L];

int main()
{
    scanf("%d", &q);


    for ( int i = 0; i < q; i++ ) {
	string a, b;
	char str[MAX_L];
	scanf("%s", str);
	a = str;
	scanf("%s", str);
	b = str;	
	memset(dp, 0, 2 * MAX_L * sizeof(int));
	
	for ( int j = 1; j <= a.length(); j++ ) {
	    for ( int k = 1; k <= b.length(); k++ ) {
		if ( a[j-1] == b[k-1] ) {
		    dp[j%2][k] = dp[(j-1)%2][k-1] + 1;
		}
		else {
		    dp[j%2][k] = max(dp[(j-1)%2][k], dp[j%2][k-1]);
		}
	    }
	}
	printf("%d\n", dp[(a.length())%2][b.length()]);
    }

    return 0;
}

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

#define MOD 1000000007
#define INF (1<<30)
#define INFL (1<<62)
#define pe(str) return cout<<(str)<<endl,0
#define px(str) cout<<(str)<<endl,exit(0)
#define accu(ac,v) cout<<setprecision(ac)<<v<<endl
#define bpc(a) __builtin_popcount(a)
#define pr(str) cout<<(str)<<endl
#define prpr(str) cout<<str<<endl
#define db(str) cerr<<"debug:"<<(str)<<endl
#define dbdb(str) cerr<<"debugs:"<<str<<endl
#define re(i,n) for(int i=0;i<(n);i++)
#define rre(i,n) for(int i=(n);i>=0;i--)
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b);i>=(a);i--)
#define bw(a,b,c) (((a)<=(b))&&((b)<=(c)))
#define hello cout<<"hello"<<endl
#define spre(a) setprecision(a)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define s3(C,T,F) ((C)?(T):(F))
#define max3(a,b,c) max((a),max((b),(c)))
#define min3(a,b,c) min((a),min((b),(c)))
#define max4(a,b,c,d) max((a),max((b),max((c),(d))))
#define min4(a,b,c,d) min((a),min((b),min((c),(d))))
#define enl cout<<endl
#define declare(t,n) t n;cin>>n

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> pii;
typedef complex<int> point;

template<class InputIterator>
void dump(InputIterator first,InputIterator last,char delim=' '){
	for(InputIterator it=first;it!=last;it++){
		if(it!=first)cout<<delim;
		cout<<*it;
	}
}

ull p(ull x,ull y){
	if(y==0) return 1;
	ull A=p(x,y/2)%MOD;
	return (y&1?((A*A)%MOD*x)%MOD: (A*A)%MOD);
	// return (y&1?((A*A)*x):(A*A));
}

template<class T>
void swp(T &a,T &b){
	T t=a; a=b; b=t;
}

int main(void){
	int dp[100][100];
	string a,b;
	int n;
	cin>>n;

	while (n--) {
		cin>>a>>b;
		re(i,a.size()) re(j,b.size()) dp[i][j]=0;
		rep(i,1,a.size()+1){
			rep(j,1,b.size()+1){
				dp[i][j]=max(dp[i-1][j-1]+(a[i-1]==b[j-1]),dp[i-1][j]);
				dp[i][j]=max(dp[i][j],dp[i][j-1]);
			}
		}
		cout<<dp[a.size()][b.size()]<<endl;
	}
	return 0;
}

C++: #include <stdio.h>

int judge(char A[], char B[]){
  int a=0, b=0, sw=0, ans=0;
  int i, j;
  int C[1001][1001];
  
  while(sw == 0){
    if(A[a] != '\0')
      a++;
    else
      sw = 1;
  }
  
  sw = 0;
  
  while(sw = 0){
    if(B[b] != '\0')
      b++;
    else
      sw = 1;
  }
  
  for(i=1; i<a+1; i++)
    C[i][0] = 0;
  for(i=1; i<b+1; i++)
    C[0][i] = 0;
  
  for(i=1; i<a+1 i++){
    for(j=1; j<b+1; j++){
      if(A[i-1] == B[j-1])
        C[i][j] = C[i-1][j-1] + 1;
      else if(C[i-1][[j] >= C[i][j-1])
        C[i][j] = C[i-1][j];
      else
        C[i][j] = C[i][j-1];
      if(max < C[i][j])
        max = c[i][j];
    }
  }
  
  return max;
}

int main(){
  char A[1000], B[1000];
  int n, i;
  
  scanf("%d", &n);
  
  for(i=0; i<n; i++){
    scanf("%s", a);
    scanf("%s", b);
    printf("%d\n", judge(a, b));
  }
  
  return 0;
}

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

int main()
{
	int n, p[N + 1], m[N + 1][N + 1];
	cin >> n;
	for (int i = 1; i <= n; i++) cin >> p[i - 1] >> p[i];
	for (int i = 1; i <= n; i++) m[i][i] = 0;

	for (int l = 2; l <= n; l++)
	{
		for (int i = 1; i <= n; i++)
		{
			int j = i + l - 1;
			m[i][j] = 1 << 21;
			for (int k = i; k <= j - 1; k++)
			{
				m[i][j] = min(m[i][j], m[i][k] + m[k + 1][j] * p[i - 1] * p[k] * p[j]);
			}
		}
	}

	cout << m[1][n] << endl;

    return 0;
}

C++: #include <iostream>
#include <vector>
#include <string>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;

void lcs(string s, string t){
    int m = s.size() + 1;
    int n = t.size() + 1;
    vector<vector<int>> dp(m, vector<int>(n));
    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 (s[i - 1] == t[j - 1])
                dp[i][j] = dp[i - 1][j - 1] + 1;
            else if (dp[i - 1][j] >= dp[i][j - 1])
                dp[i][j] = dp[i - 1][j];
            else
                dp[i][j] = dp[i][j - 1];
        }
    }
    cout << dp[m - 1][n - 1] << endl;
}

int main(){
    int q;
    cin >> q;
    string s, t;
    rep(k, q) {
        cin >> s >> t;
        lcs(s, t);
    }
    return 0;
}