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 <vector>

using ll = long long;
using namespace std;

/* initialize */
int lcs(string A, string B){
    int m = A.length(), n = B.length();
    int c[m+1][n+1];
    int maxl = 0;
    A = ' ' + A;
    B = ' ' + B;
    for (int i = 0; i <= m; ++i) c[i][0]=0;
    for (int i = 1; i <= n; ++i) c[0][i]=0;
    for (int i = 1; i <= m; ++i) {
        for (int j = 1; j <= n; ++j) {
            if (A[i]==B[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;
};
/* main */
int main() {
    int n;
    cin >> n;
    string s1, s2;
    for (int i = 0; i < n; ++i) {
        cin >> s1 >> s2;
        int s = lcs(s1, s2);
        cout << s << "\n";
    }
    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 = 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++: #include <iostream>
#include <algorithm>
#include<string>
using namespace std;

static const int N = 1000;
static int dp[N + 1][N + 1];

int lcs(string x, string y)
{
    int m = x.length();
    int n = y.length();
    x = ' ' + x;
    y = ' ' + y;

    dp[0][0] = 0;
    for (int i = 1; i <= m; i++)
        dp[i][0] = 0;
    for (int j = 1; j <= n; j++)
        dp[0][j] = 0;

    int res = 0;
    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]);
        }
    }

    return dp[m][n];
}

int main()
{
    int n;
    cin >> n;
    string x1, x2;
    for (int i = 0; i < n; i++)
    {
        cin >> x1 >> x2;
        cout << lcs(x1, x2) << endl;
    }
    return 0;
}

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

using ll = long long;
using namespace std;
constexpr ll inf = 1e15;
constexpr ll mod = 1e9+7;

ll dp[1001][1001] = {0};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int Q;
    cin>>Q;
    for (int q = 0; q < Q; q++) {
        string X, Y;
        cin>>X>>Y;

        for (int i = 1; i <= X.length(); i++) {
            for (int j = 1; j <= Y.length(); j++) {
                dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
                if (X[i-1] == Y[j-1]) dp[i][j] = max(dp[i][j], dp[i-1][j-1]+1);
            }
        }
        cout<<dp[X.length()][Y.length()]<<endl;
    }
    return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
#define MAX 1100

int temp[MAX][MAX];
int main(){
	int q;
	string x, y;
	
	cin>>q;
	
	for(int i = 1; i <= q; i++){
		cin>>x>>y;
		int sx = x.size() ,sy = y.size();
		for(int j = 0; j <= sx; j++)for(int k = 0; k <= sy; k++)temp[j][k] = 0;
		for(int j = 0; j < sx; j++){
			for(int k = 0; k < sy; k++){
				if(x[j] == y[k]){
					temp[j+1][k+1] = max(temp[j][k]+1,temp[j+1][k+1]);
				} else temp[j+1][k+1] = max(temp[j+1][k],temp[j][k+1]);
			}
		}
		cout<<temp[sx][sy]<<endl;
	}
	
	return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <string>
#include <sstream>
#include <algorithm>
#include <iomanip>
#include <iostream>

#define VARIABLE(x) cerr << #x << "=" << x << endl
#define BINARY(x) static_cast<bitset<16> >(x);
#define if_range(x, w, h) if (w <= x && x <= h)
#define BitCheck(a,b)   (a >> b) & 1
#define BitSet(a,b)       a |= (1 << b)
#define BitunSet(a,b)    a &= ~(1 << b)

int compare_int(const void* a, const void* b) { return *(int*) a - *(int*) b; }

int main() {
	int n, m, a, dp[102][102] = { 0 };
	char s[1001], t[1001];
	scanf("%d", &a);
	for (int k = 0; a > k; k++) {
		scanf("%d %d %s %s", &n, &m, s, t);
		for (int i = 1; n >= i; i++) {
			for (int j = 1; m >= j; j++) {
				if (s[i - 1] == t[j - 1])dp[i][j] = dp[i - 1][j - 1] + 1;
				else dp[i][j] = __max(dp[i - 1][j], dp[i][j - 1]);
			}
		}
		printf("%d\n", dp[n][m]);
	}
	return 0;
}

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

void LCS(string X, string Y){
    X = ' ' + X; //＋演算子でX[0]に空白を挿入
    Y = ' ' + Y;
    int C[X.length()][Y.length()];
    
    for (int i = 0; i < X.length(); i++){
        C[i][0] = 0;
    }
    for (int i = 0; i < Y.length(); i++){
        C[0][i] = 0;
    }
    
    for (int i = 1; i < X.length(); i++){
        for (int j = 1; j < Y.length(); j++){
            if ( X[i] == Y[j] ) C[i][j] = C[i-1][j-1] + 1;
            else C[i][j] = max(C[i][j-1], C[i-1][j]);
        }
    }
    cout << C[X.length()-1][Y.length()-1] << endl;
    
}

int main(){
    int n;
    string X, Y;
    cin >> n;
    
    for (int i = 0; i < n; i++ ){
        cin >> X;
        cin >> Y;
        LCS(X, Y);
    }
    
    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;
}