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 <iostream>
#include <string>
#include <stdio.h>
#include <algorithm>
#define MAX 100000


int lcs(std::string X, std::string Y) {
    int c[MAX][MAX];
    int maxl = 0;
    int m = X.size();
    int n = Y.size();
    for (int i = 1; i <= m; i++) {
        c[i][0] = 0;
    }
    for (int i = 1; i <= n; i++) {
        c[0][i] = 0;
    }
    X = ' ' + X;
    Y = ' ' + Y;
    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] = std::max(c[i-1][j], c[i][j-1]);
            }
            maxl = std::max(maxl, c[i][j]);
        }
    }
    return maxl;
}

int main() {
    std::string s1, s2;
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
        std::cin >> s1 >> s2;
        int a = lcs(s1, s2);
        printf("%d\n", lcs(s1, s2));
    }
    
    return 0;
}

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

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

using ll = long long;
using pii  = pair<int, int>;
using pll = pair<ll, ll>;
#define ull unsigned long long
#define ld long double
#define vi vector<int>
#define vll vector<ll>
#define vc vector<char>
#define vs vector<string>
#define vpii vector<pii>
#define vpll vector<pll>

#define rep(i, n) for (int i = 0, i##_len = (n); i < i##_len; i++)
#define rep1(i, n) for (int i = 1, i##_len = (n); i <= i##_len; i++)
#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 pb push_back
#define mp make_pair

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

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(){
    int q;
    cin >> q;
    rep(i, q) {
        string x, y;
        cin >> x >> y;
        vi l;
        rep(k, sz(y)) {
            int xbi = 0;
            bool skip = false;
            rep(j, sz(l)) {
                int p = x.find(y[k], xbi);
                if (p == (int)string::npos) {
                    skip = true;
                    break;
                }
                xbi = l[j];
                l[j] = min(l[j], p+1);
            }
            if (!skip) {
                int p = x.find(y[k], xbi);
                if (p != (int)string::npos) l.pb(p+1);
            }
        }
        cout << sz(l) << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<string>
using namespace std;
int dp[1001][1001];
string x,y;

int calc_dp(int m, int n){
  for ( int i = 0; i <= m; i++){dp[i][0] = 0; }
  for ( int i = 0; i <= n; i++){dp[0][i] = 0; }

  for ( int i = 1; i <= m; i++){
    for ( int l = 1; l <= n; l++){
      if(x[i] == y[l]){
        dp[i][l] = dp[i-1][l-1] + 1;
      } else {
        dp[i][l] = max(dp[i][l-1], dp[i-1][l]);
      }
    }
  }
  return dp[m][n];
}

int main(){
  int q;
  cin >> q;
  // init
  for ( int i = 0 ; i < q; i++){

    string X, Y;
    cin >> X >> Y;
    x = ' ' + X;
    y = ' ' + Y;

    cout << calc_dp(X.length(), Y.length()) << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<cstdio>
#include<string>
using namespace std;
static const int N = 1000;
int lcs(string X,string Y)
{
  int c[N+1][N+1];
  int m = X.size();
  int n = Y.size();
  int maxl = 0;
  X = ' '+X;
  Y = ' '+Y;
  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;
}
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++: def lcs(l1,l2):
    dp=[[0 for x in range(len(l2)+1)] for y in range(len(l1)+1)]

    for i in range(1,len(l1)+1):
        for j in range(1,len(l2)+1):
            if l1[i-1]==l2[j-1]:
                dp[i][j]=dp[i-1][j-1]+1
            else:
                dp[i][j]=max(dp[i-1][j],dp[i][j-1])
                
    return dp[len(l1)][len(l2)]


a=[]
n=int(input())
for i in range(n):
    l1=list(input())
    l2=list(input())
    a+=[lcs(l1,l2)]

for i in range(n):
    print(a[i])

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

static const long N = 1000;

long lcs(string X, string Y){
	long c[N + 1][N + 1];
	long m = X.size();
	long n = Y.size();
	long maxl = 0;
	X = ' ' + X;
	Y = ' ' + Y;
	for (long i = 1; i <= m; i++) c[i][0] = 0;
	for (long j = 1; j <= n; j++) c[0][j] = 0;

	for (long i = 1; i <= m; i++){
		for (long 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 = c[i][j];
		}
	}

	return maxl;
}

int main(){
	string s1, s2;
	long n;
	cin >> n;
	for (long i = 0; i < n; i++){
		cin >> s1 >> s2;
		cout << lcs(s1, s2) << endl;
	}
	return 0;
}

C++: #include <stdio.h>

int score[1010][1010];

int max2 (int a, int b){
  if (a >= b) return a;
  else return b;
}

int len_of_str(const char s[]){
  int num = 0;

  while(s[num]) num++;

  return num;
}


int main() {
  char a[1010];
  char b[1010];
  int datanum;
  scanf("%d",&datanum);
  for(int c = 0; c < datanum; c++){

  scanf("%999s",a);
  scanf("%999s",b);
  int num1 = len_of_str(a);
  int num2 = len_of_str(b);


  for(int i = num1; i > 0; i--) a[i] = a[i - 1];
  a[0] = ' ';
  for(int j = num2; j > 0; j--) b[j] = b[j - 1];
  b[0] = ' ';

  for(int i = 0; i <= num1; i++) score[i][0] = 0;
  for(int j = 0; j <= num2; j++) score[0][j] = 0;

  int maximum = 0;

  for(int i = 1; i<= num1; i++){
    for (int j = 1; j <= num2; j++){
      if (a[i] == b[j])score[i][j] = score[i-1][j-1] + 1;
      else if (a[i] != b[j]) score[i][j] = max2(score[i][j-1],score[i-1][j]);
      maximum = max2(maximum,score[i][j]);
    }
  }



  printf("%d\n",maximum);
}
  return 0;
}