Go: package main

import (
	. "fmt"
    "math"
)

// func init() { Println("----------------------------------------") }

func main() {
    const L_MAX = 1003

	var q int
	Scanf("%d", &q)
	X := make([]string, 0, 150)
	Y := make([]string, 0, 150)
	for i := 0; i < 2 * q; i++ {
	    var tmp string
	    Scanf("%s", &tmp)

	    if i % 2 == 0 {
	        X = append(X, tmp)
	    } else {
	        Y = append(Y, tmp)
	    }
	}

    for i := 0; i < q; i++ {
        dp := make([][]int, L_MAX)
        for k, _ := range dp {
            dp[k] = make([]int, L_MAX)
        }

        x, y := X[i], Y[i]

        // init
        isXFound := false
        for c := 0; c < len(x); c++ {
            if isXFound || y[0] == x[c] {
                dp[0][c] = 1
                isXFound = true
            }
        }
        isYFound := false
        for r := 0; r < len(y); r++ {
            if isYFound || x[0] == y[r] {
                dp[r][0] = 1
                isYFound = true
            }
        }

        for r := 1; r < len(y); r++ {
            for c := 1; c < len(x); c++ {
                // dp[r][c]
                if x[c] == y[r] {
                    dp[r][c] = int(math.Max(float64(dp[r - 1][c - 1] + 1), float64(dp[r][c])))
                }

                dp[r][c] = int(math.Max(float64(dp[r][c]), math.Max(float64(dp[r - 1][c]), float64(dp[r][c - 1]))))
            }
        }
        Println(dp[len(y) - 1][len(x) - 1])

        // LCSも求めておく
        // ans := ""
        // r, c := len(y) - 1, len(x) - 1
        // for r >= 0 && c >= 0 {
        //     if y[r] == x[c] {
        //         ans = string(x[c]) + ans
        //         r--
        //         c--
        //     } else {
        //         if dp[r - 1][c] > dp[r][c - 1] {
        //             r--
        //         } else {
        //             c--
        //         }
        //     }
        // }
        // Println(ans)
    }
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define nyan "(=^･ω･^=)"
using namespace std;

const int mod = 1e9 + 7;
const long long INF = 1LL<<60;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
//using ll = long long;
//using P = pair<int,int>;

int main(){
    int q;
    cin >> q;
    
    rep(i, q){
        string x, y;
        cin >> x >> y;
        
        int n = x.size();
        int m = y.size();
        
        // dp[i][j] : sのi番目, tのj番目までに対する 
        // longest common subsequenceの長さ
        vector<vector<int> > dp(n+1, vector<int>(m+1));
        
        for (int i = 0; i < n; i++){
            for (int j = 0; j < m; j++){
                
                if (x[i] == y[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;
    }
}

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

using namespace std;

int main(){
  string X,Y;
  int n;
  cin>>n;
  int ans[n];
  int l=0;
 int point;

  for(int i=0;i<n;i++){
    ans[i]=0;
  }

  for(int m=0;m<n;m++){
  cin>>X>>Y;
 int N[X.size()+1][Y.size()+1];

  for(int i=0;i<=X.size();i++){
    for(int j=0;j<=Y.size();j++){

      N[i][j]=0;
}
  }

 
 

  for(int i=1;i<=X.size();i++){
    for(int j=1;j<=Y.size();j++){
      if(X[i-1]==Y[j-1]){
	point=1;
	
      }else{
	point=0;
      }
       N[i][j]=max({N[i-1][j],N[i][j-1],N[i-1][j-1]+point});
       point=0;
}
   
  }
  ans[l]=N[X.size()][Y.size()];
  l++;

  }
  cout<<ans[0]<<endl;
 cout<<ans[1]<<endl;
 cout<<ans[2]<<endl;

 return 0;
}

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

int main(){
    int N; cin >> N;
    for (int _ = 0; _ < N*2;_ += 2){
        string A,B;
        cin >> A >> B;
        
        vector<vector<int>> dp(A.size() +1 ,vector<int> (B.size() + 1,0));
        for (int i = 0;i < A.size();i ++){
            for(int j = 0; j < B.size(); j++){
                if(A[i] == B[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[A.size()][B.size()] << endl;
    }
}

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++: /**
 * @copyright (c) 2020 Daisuke Hashimoto
 */

#include <bits/stdc++.h>
using namespace std;
using Pair = pair<int64_t, int64_t>;
constexpr int64_t kInf = INT64_MAX / 2L;

// std::cout << std::setprecision(20) << 1.1 << endl;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  int64_t Q;
  cin >> Q;
  for (int64_t q = 0; q < Q; ++q) {
    string s, t;
    cin >> s >> t;
    const int64_t SL = static_cast<int64_t>(s.length());
    const int64_t TL = static_cast<int64_t>(t.length());
    vector<vector<int64_t>> dp(SL + 1, vector<int64_t>(TL + 1, 0));
    for (int64_t i = 1; i <= SL; ++i) {
      for (int64_t j = 1; j <= TL; ++j) {
        dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
        if (s[i - 1] == t[j - 1]) {
          dp[i][j] = max(dp[i][j], 1 + dp[i - 1][j - 1]);
        }
      }
    }
    cout << dp[SL][TL] << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<string>
#include<set>
#include<map>

using namespace std;

const int MAX_SIZE = 1000;

int LCS(string& X, string& Y,int dp[MAX_SIZE][MAX_SIZE], int X_pos, int Y_pos) {
	if (Y_pos == Y.length() || X_pos == X.length()) {
		return 0;
	}
	int res;

	if (dp[X_pos][Y_pos + 1] == -1) {
		dp[X_pos][Y_pos + 1] = LCS(X, Y, dp, X_pos, Y_pos + 1);
	}
	res = dp[X_pos][Y_pos + 1];

	for (int i = X_pos; i < X.length(); i++) {
		if (X[i] == Y[Y_pos]) {
			if (dp[i + 1][Y_pos + 1] == -1) {
				dp[i + 1][Y_pos + 1] = LCS(X, Y, dp, i + 1, Y_pos + 1);
			}
			res = max(dp[i + 1][Y_pos + 1] + 1, res);
		}
	}
	return res;
}

int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		string X, Y;
		int dp[MAX_SIZE][MAX_SIZE];

		cin >> X;
		cin >> Y;

		for (int i = 0; i < X.length() + 1; i++) {
			for (int j = 0; j < Y.length() + 1; j++) {
				dp[i][j] = -1;
			}
		}

		cout << LCS(X, Y, dp, 0, 0) << endl;
	}
	return 0;
}