Go: package main

import (
	"fmt"
)

func main() {
	var q int
	fmt.Scan(&q)

	for i := 0; i < q; i++ {
		var x, y string
		fmt.Scan(&x)
		fmt.Scan(&y)

		xs := []rune(x)
		ys := []rune(y)

		xn := len(xs)
		yn := len(ys)
		dp := make([][]int, xn+1)
		for j := 0; j <= xn; j++ {
			dp[j] = make([]int, yn+1)
		}

		for j := 1; j <= xn; j++ {
			for k := 1; k <= yn; k++ {
				dp[j][k] = max(dp[j-1][k], dp[j][k-1])
				if xs[j-1] == ys[k-1] {
					dp[j][k] = max(dp[j][k], dp[j-1][k-1] + 1)
				} else {
					dp[j][k] = max(dp[j][k], dp[j-1][k-1])
				}
			}
		}
		fmt.Println(dp[xn][yn])
	}
}

func max(a, b int) int {
	if a < b {
		return b
	} else {
		return a
	}
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <cstdio>
#include <cstdlib>
#include <string>
#include <iostream>
#include <queue>

using namespace std;

const char *X, *Y;
int X_length, Y_length;

int table_lcs[1001][1001];

int lcs(int x_begin, int y_begin) {
	int i, j, to;
	int max = 0;
	int v_lcs;
	bool alreadySeenTable[256];
	if (table_lcs[x_begin][y_begin] != -1) {
		return table_lcs[x_begin][y_begin];
	}
	
	for (i = 0; i < 256; i++) {
		alreadySeenTable[i] = false;
	}
	i = x_begin;
	to = Y_length-1;
	while(i <= X_length-1) {
		j = y_begin;
		if (alreadySeenTable[X[i]] == true) {
			i++;
			continue;
		}
		bool found = false;
		while (j <= to) {
			if (X[i] == Y[j]) {
				v_lcs = lcs(i + 1, j + 1) + 1;
				if (v_lcs > max) {
					max = v_lcs;
				}
				found = true;
				break;
			}
			else {
				j++;
			}
		}
		if (found == false) {
			alreadySeenTable[X[i]] = true;
			i++;
		}
		else {
			alreadySeenTable[X[i]] = true;
			i++;
			to = j - 1;
		}
	}
	return table_lcs[x_begin][y_begin] = max;
}

int lcs2(int x_begin, int y_begin) {
	int i, j, to;
	int max = 0;
	int v_lcs;
	if (table_lcs[x_begin][y_begin] != -1) {
		return table_lcs[x_begin][y_begin];
	}

	i = x_begin;
	to = Y_length - 1;
	while (i <= X_length - 1) {
		j = y_begin;
		bool found = false;
		while (j <= to) {
			if (X[i] == Y[j]) {
				v_lcs = lcs(i + 1, j + 1) + 1;
				if (v_lcs > max) {
					max = v_lcs;
				}
				found = true;
				break;
			}
			else {
				j++;
			}
		}
		if (found == false) {
			i++;
		}
		else {
			i++;
			to = j - 1;
		}
	}
	return table_lcs[x_begin][y_begin] = max;
}

int main() {

	int N;
	cin >> N;
	string stringX, stringY;

	for (int i = 1; i <= N; i++) {
		for (int i = 0; i < 1001; i++) {
			for (int j = 0; j < 1001; j++) {
				table_lcs[i][j] = -1;
			}
		}
		cin >> stringX >> stringY;
		X = stringX.c_str();
		X_length = stringX.size();
		Y = stringY.c_str();
		Y_length = stringY.size();
		printf("%d\n", lcs(0, 0));
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;

const long long MOD = 1000000007;
const long long INF = 1LL << 60;

// change minimum change maximum
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;
}

void solve()
{
  string S, T;
  cin >> S >> T;
  int N, M;
  N = S.size(), M = T.size();
  ll dp[N + 1][M + 1];
  for (int i = 0; i < N + 1; i++)
  {
    for (int j = 0; j < M + 1; j++)
    {
      dp[i][j] = 0;
    }
  }
  for (int i = 0; i < N; i++)
  {
    for (int j = 0; j < M; j++)
    {
      if (S[i] == T[j])
      {
        dp[i + 1][j + 1] = dp[i][j] + 1;
      }
      else
      {
        dp[i + 1][j + 1] = max(dp[i][j + 1], dp[i + 1][j]);
      }
    }
  }
  cout << dp[N][M] << endl;
}

int main()
{
  int q;
  cin >> q;
  for (int i = 0; i < q; i++)
    solve();
  return 0;
}

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

int LCS(string p, string q) {
	vector<vector<int>> f(p.size()+1, vector<int>(q.size()+1,0));
	int t;
	for (int i = 1; i <= p.size(); i++) {
		for (int j = 1; j <= q.size(); j++) {
			if (p[i-1] == p[j-1])
				f[i][j] = f[i - 1][j - 1] + 1;
			else if (f[i][j - 1] > f[i - 1][j - 1])
				f[i][j] = f[i][j - 1];
			else
				f[i][j] = f[i - 1][j];
		}
	}
	return f[p.size()][q.size()];
}

int main() {
	int n;
	string p[150];
	cin >> n;
	for (int i = 0; i < n; i ++) {
		cin >> p[2*i] >> p[2*i + 1];
	}
	for (int i = 0; i < n; i++) {
		cout << LCS(p[2*i], p[2 * i + 1])<<endl;
	}
	return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <cstdio>
#include <cstdlib>
#include <string>
#include <iostream>
#include <queue>

using namespace std;

const char *X, *Y;

int lcs(int x_begin, int y_begin) {
	int max = 0;
	for (int i = x_begin; X[i] != '\0'; i++) {
		for (int j = y_begin; Y[j] != '\0'; j++) {
			if (X[i] == Y[j]) {
				int v_lcs = lcs(i + 1, j + 1);
				if (v_lcs + 1 > max) {
					max = v_lcs + 1;
				}
			}
		}
	}
	return max;

}

int main() {
	int N;
	cin >> N;
	string stringX, stringY;
	for (int i = 1; i <= N; i++) {
		cin >> stringX >> stringY;
		X = stringX.c_str();
		Y = stringY.c_str();
		printf("%d\n", lcs(0, 0));
	}
	return 0;
}

C++: #include <iostream>
#include <cmath>
#include <vector>

constexpr int MAX = 1000;
char ls[MAX];
char rs[MAX];
int table[MAX + 1][MAX + 1];


void calc_lcs() {
    scanf("%s", ls);
    scanf("%s", rs);
    int l_len = int(std::strlen(ls));
    int r_len = int(std::strlen(rs));
    for (int i = 0; i < l_len; i++) {
        table[i][0] = 0;
    }
    for (int i = 0; i < r_len; i++) {
        table[0][i] = 0;
    }

    for (int l_i = 1; l_i < l_len + 1; l_i++) {
        for (int r_i = 1; r_i < r_len + 1; r_i++) {
            if (ls[l_i - 1] == rs[r_i - 1]) {
                table[l_i][r_i] = table[l_i - 1][r_i - 1] + 1;
            } else {
                table[l_i][r_i] = std::max(table[l_i][r_i - 1], table[l_i - 1][r_i]);
            }
        }
    }
    std::cout << table[l_len][r_len] << std::endl;
}

int main() {
    int N;
    scanf("%d", &N);
    for (int i = 0; i < N; i++) {
        calc_lcs();
    }
}

C++: #include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <cstring>
using namespace std;

typedef long long ll;
#define rep(i, a, b) for (ll i=(a); i<(b); i++)
#define all(obj) (obj).begin(), (obj).end()
#define fi first
#define sc second
#define pb push_back
#define str to_string
const ll INF = 1e18;
const ll MOD = 1e9 + 7;
void chmax(ll &a, ll b) { a = max(a, b); }
void chmin(ll &a, ll b) { a = min(a, b); }

ll dp[1010][1010];

ll LCS(string a, string b) {
    int N = a.size();
    int M = b.size();
    memset(dp, 0, sizeof(dp));

    rep(i, 0, N+1) rep(j, 0, M+1) {
        if (i < N) {
            chmax(dp[i+1][j], dp[i][j]);
        }
        if (j < M) {
            chmax(dp[i][j+1], dp[i][j]);
        }
        if (i < N && j < M && a[i] == b[j]) {
            chmax(dp[i+1][j+1], dp[i][j]+1);
        }
    }
    return dp[N][M];
}

int main() {
    int Q;
    string a, b;
    cin >> Q;
    rep(i, 0, Q) {
        cin >> a;
        cin >> b;
        cout << LCS(a, b) << endl;
    }
    return 0;
}