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 <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(ans < C[i][j])
        ans = C[i][j];
    }
  }
  
  return ans;
}

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>
#include<string>
using namespace std;

int Longest(string x, string y) {
  int L[1001][1001];
  int maxl = -1;
  int xlen = x.size();
  int ylen = y.size();

  x = ' ' + x;
  y = ' ' + y;

  for (int i = 1; i <= xlen; i++) L[i][0] = 0;
  for (int j = 1; j <= ylen; j++) L[0][j] = 0;

  for (int i = 1; i <= xlen; i++) {
    for (int j = 1; j <= ylen; j++) {
      if (x[i] == y[j])
        L[i][j] = L[i-1][j-1] + 1;
      else
        L[i][j] = max(L[i][j-1], L[i-1][j]);

      maxl = max(maxl, L[i][j]);
    }
  }

  return maxl;
}

int main() {
  string X, Y;
  int n;
  int result[1001];

  cin >> n;

  for (int i = 0; i < n; i++) {
    cin >> X;
    cin >> Y;
    result[i] =  Longest(X, Y);
    cout << result[i] << endl;
  }




  return 0;
}

C++: #include<iostream>
#include<string.h>
#include<algorithm>

#define MAX 10000

using namespace std;

int lcs(string s1, string s2) {
    int C[MAX+1][MAX+1];
    int m = s1.size();
    int n = s2.size();
    for (int i = 0; i <= m; ++i) {
        C[i][0] = 0;
    }
    for (int j = 0; j <= n; ++j) {
        C[0][j] = 0;
    }

    for (int i = 1; i <= m; ++i) {
        for (int j = 1; j <= n; ++j) {
            if (s1[i-1] == s2[j-1]) {
                C[i][j] = C[i-1][j-1] + 1;
            }
            else {
                C[i][j] = max(C[i][j-1], C[i-1][j]);
            }
        }
    }

    return C[m][n];
}

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

C++: #include<iostream>
#include<algorithm>
#include<string>

struct info {
	int max{};
	bool done{};
};

int build_dp(info[1000][1000], int, int);
std::string str_x, str_y;

int main()
{
	int q;

	std::cin >> q;
	for (int i = 0; i < q; ++i)
	{
		info dp[1000][1000] {};
		std::cin >> str_x >> str_y;
		std::cout << build_dp(dp, str_x.size() - 1, str_y.size() - 1) << std::endl;
	}
	return 0;
}

int build_dp(info dp[1000][1000], int x_i, int y_i)
{
	if (x_i < 0 || y_i < 0) return 0;
	if (dp[x_i][y_i].done == true) return dp[x_i][y_i].max;

	if (str_x[x_i] == str_y[y_i])
	{
		dp[x_i][y_i].max = build_dp(dp, x_i - 1, y_i - 1) + 1;
		dp[x_i][y_i].done = true;
	}
	else
	{
		dp[x_i][y_i].max = std::max(build_dp(dp, x_i - 1, y_i), build_dp(dp, x_i, y_i - 1));
		dp[x_i][y_i].done = true;
	}
	return dp[x_i][y_i].max;
}

C++: #include <iostream>

using namespace std;

int ans(string a, string b) {
  int n = a.size();
  int m = b.size();
  int memo[n+1][m+1];
  for (int i = 0; i <= n; i++) {
    for (int j = 0; j <= m; j++) {
      memo[i][j] = 0;
    }
  }

  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      int res = max(memo[i-1][j], memo[i][j-1]);
      if (a[i-1] == b[j-1]) {
        res = max(res, memo[i-1][j-1] + 1);
      } else {
        res = max(res, memo[i-1][j-1]);
      }
      memo[i][j] = res;
    }
  }
  
  return memo[n][m];
}

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

  for (int i = 0; i < q; i++) {
    string a, b;
    cin >> a >> b;
    
    cout << ans(a, b) << endl;
  }

  return 0;
}

C++: #include<iostream>

using namespace std;

int dp[1001][1001];

int main(){
    int q, m, n;
    cin >> q;

    while(q-- > 0){
        string x, y;
        cin >> x >> y;
        m = x.length();
        n = y.length();
        for(int i = 0; i <= m; i++) dp[i][0];
        for(int i = 0; i <= n; i++) dp[0][i];

        for(int i = 1; i <= m; i++){
            for(int j = 1; j <= n; j++){
                if(x[i] == y[j])    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] << endl;
    }

    return 0;
}

C++: 

#include<iostream>
#include<string>
#include<algorithm>
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 = 0; i <= m; i++) c[i][0] = 0;
    for(int j = 0; 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++: #include<iostream>
#include<fstream>
#include<algorithm>
#include<string>
using namespace std;

const int MAX = 1000;
static int n, m;
static char S[150][MAX], T[150][MAX];
static int ans[150][MAX];
void solve(int in)
{
	int count_max = 0;
	for (int i = n - 1; i >= 0; i--) {
		count_max = 0;
		for (int j = n - 1; j >= 0; j--) {
			int count = 0;
			int tem_i = i, tem_j = j;
			//?????´??????????????????????????????????????´????????´????????¢?´¢??????
			if (S[in][tem_i] == T[in][tem_j] && S[in][tem_i + 1] == T[in][tem_j + 1] && tem_i + 1 < n && tem_j + 1 < m)
				break;
			while (S[in][tem_i] == T[in][tem_j]&& tem_i>=0 && tem_j>=0 ) {
				count++;
				tem_i--;
				tem_j--;
			}
			if (count_max < count) {
				count_max = count;
			}
		}
		ans[in][i] = count_max;
		//???????????§??§i??????????????§?????¨??????????±???????.
	}
}
int main()
{
	int q;
	cin >> q;
	for (int i = 0; i < q; i++) {
		cin >> S[i];
		cin >> T[i];
		n = strlen(S[i]);
		m = strlen(T[i]);
		solve(i);
	}

	for (int i = 0; i < q; i++)
	cout << *max_element(&ans[i][0], &ans[i][n]) << endl;

	return 0;
}