Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	for i := 0; i < n; i++ {
		x := getNextString(scanner)
		y := getNextString(scanner)

		fmt.Fprintln(writer, lcs(x, y))
	}

	writer.Flush()
}

func lcs(x, y string) int {
	lx := len(x)
	ly := len(y)
	dp := make([][]int, lx+1)
	for i := 0; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
	}
	for i := 0; i < lx; i++ {
		for ii := 0; ii < ly; ii++ {
			if x[i] == y[ii] {
				dp[i+1][ii+1] = dp[i][ii] + 1
				continue
			}
			dp[i+1][ii+1] = dp[i][ii+1]
			if dp[i+1][ii] > dp[i+1][ii+1] {
				dp[i+1][ii+1] = dp[i+1][ii]
			}
		}
	}
	return dp[lx][ly]
}

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

using namespace std;
// ascending order
#define vsort(v) sort(v.begin(), v.end())
// descending order
#define vsort_r(v) sort(v.begin(), v.end(), greater<int>())
#define vunique(v) v.erase(unique(v.begin(), v.end()), v.end())
#define mp make_pair
#define ts(x) to_string(x)
#define rep(i, a, b) for(int i = (int)a; i < (int)b; i++)
#define repm(i, a, b) for(int i = (int)a; i > (int)b; i--)
#define bit(a) bitset<8>(a)
#define des_priority_queue priority_queue<int, vector<int>, greater<int> >
typedef long long ll;
typedef pair<int, int> P;
const ll INF = 1e18;

#define MAX_V 1000000

int solve(string x, string y) {
  int dp[x.size() + 1][y.size() + 1];
  memset(dp, 0, sizeof(dp));
  rep(i, 0, x.size()) {
    rep(j, 0, y.size()) {
      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]);
      }
    }
  }
  return dp[x.size()][y.size()];
}

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

  int q;
  cin >> q;
  vector<int> rsl;
  rep(i, 0, q) {
    string x, y;
    cin >> x >> y;
    rsl.push_back(solve(x, y));
  }
  rep(i, 0, rsl.size()) cout << rsl[i] << endl;
}

C++: #include<iostream>
#include<vector>b
using namespace std;
int main()
{
	int kurikaeshi;
	vector<int> answer;
	cin >> kurikaeshi;
	for (int variable = 0;variable < kurikaeshi;++variable) {
		char X[1024], Y[1024];
		int LX = 0, LY = 0;
		vector<vector<int>> L;
		cin >> X >> Y;
		for (int i = 0;X[i] != 0;++i) LX += 1;
		for (int j = 0;Y[j] != 0;++j) LY += 1;
		L.resize(LX+1);
		for (int k = 0;k < LX + 1;++k) L[k].resize(LY+1);
		for (int i = 0;i<LX+1;++i) {
			for (int j = 0;j<LY+1;++j) {
				if (i == 0 || j == 0) {
					L[i][j] = 0;
				}
				else if (X[i-1] == Y[j-1]) {
					L[i][j] = L[i][j-1] + 1;
				}
				else {
					L[i][j] = L[i-1][j] > L[i][j-1] ? L[i-1][j] : L[i][j-1];
				}
			}
		}
		answer.push_back(L[LX][LY]);
	}
	for (int variable = 0;variable < kurikaeshi;++variable) {
		cout << answer[variable] << endl;
	}
}

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

using namespace std;
using ll = long long;


int main()
{
    int q;
    cin >> q;
    vector<int> ans;

    while(q--) {

        string s, t;
        cin >> s >> t;
        int n = s.size(), m = t.size();
        vector<vector<int>> dp(n + 1, vector<int>(m + 1)); //dp[i][j] := sのi文字目, tのj文字目まで見た時の最長
        
        for(int i = 0; i < n; i++) {
            for(int j = 0; j < m; j++) {

                if(s[i] == t[j]) {
                    dp[i + 1][j + 1] = max({dp[i + 1][j], dp[i][j + 1], dp[i][j] + 1});
                }else{
                    dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
                }
            }
        }
        ans.push_back(dp[n][m]);
    }
    for(auto i : ans) {
        cout << i << endl;
    }

}

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

#define rep(i, m, n) for(int(i) = (int)(m); i < (int)(n); ++i)
#define rep2(i, m, n) for(int(i) = (int)(n)-1; i >= (int)(m); --i)
#define REP(i, n) rep(i, 0, n)
#define REP2(i, n) rep2(i, 0, n)
#define all(hoge) (hoge).begin(), (hoge).end()
#define en '\n'
using ll = long long;
using ull = unsigned long long;
using ld = long double;
template <class T>
using vec = vector<T>;
template <class T>
using vvec = vector<vec<T>>;
typedef pair<ll, ll> P;
constexpr long long INF = 1LL << 60;
constexpr int INF_INT = 1 << 25;
constexpr long long MOD = (ll)1e9 + 7;
//constexpr long long MOD = 998244353LL;
using ld = long double;
static const ld pi = 3.141592653589793L;
typedef vector<ll> Array;
typedef vector<Array> Matrix;

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;
}

struct Edge {
    ll to, rev;
    long double cap;
    Edge(ll _to, long double _cap, ll _rev) {
        to = _to;
        cap = _cap;
        rev = _rev;
    }
};
using Edges = vector<Edge>;
using Graph = vector<Edges>;

void add_edge(Graph &G, ll from, ll to, long double cap, bool revFlag,
              long double revCap) {
    G[from].push_back(Edge(to, cap, (ll)G[to].size()));
    if(revFlag)
        G[to].push_back(Edge(from, revCap, (ll)G[from].size() - 1));
}

void solve() {
    string s, t;
    cin >> s >> t;
    ll n = s.size();
    ll m = t.size();

    Matrix dp(n + 1, Array(m + 1, 0));

    REP(i, n + 1) {
        REP(j, 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 and j < m and s[i] == t[j])
                chmax(dp[i + 1][j + 1], dp[i][j] + 1);
        }
    }
    cout << dp[n][m] << en;
}

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

    //solve();

    ll t;
    cin >> t;
    REP(i, t) { solve(); }

    return 0;
}

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

#define REP(i, n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()
const int INF = 1e9;

using namespace std;
int dp[1005][1005];

int main() {
    int n; cin >> n;
    REP(k, n){
        REP(i, 1005) REP(j, 1005) dp[i][j] = 0;
        string a, b;
        cin >> a >> b;
        REP(i, a.length()){
            string q = a.substr(i, 1);
            REP(j, b.length()){
                string t = b.substr(j, 1);
                if(q == t){
                    if(i == 0 || j == 0)
                        dp[i][j] = 1;
                    else
                        dp[i][j] = (dp[i-1][j] > dp[i][j-1]) ? max(dp[i-1][j-1] + 1, dp[i-1][j]) : max(dp[i-1][j-1] + 1, dp[i][j-1]);
                }
                else if (i != 0 && j != 0)
                    dp[i][j] = (dp[i-1][j] > dp[i][j-1]) ? dp[i-1][j] : dp[i][j-1];
                else if (i != 0)
                    dp[i][j] = dp[i-1][j];
                else
                    dp[i][j] = dp[i][j-1];
            }
        }
        cout << dp[a.length()-1][b.length()-1] << endl;
    }
    return 0;
}