Go: package main

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

var (
	nstr   func() string
	stdout *bufio.Writer
)

func init() {
	nstr = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func main() {
	defer stdout.Flush()

	n := nint()
	xList := make([]string, n)
	yList := make([]string, n)

	for i:=0;i<n ;i++  {
		xList[i] = nstr()
		yList[i] = nstr()
	}

	for i := 0; i<n	; i++  {
		fmt.Println(lcs(xList[i], yList[i]))
	}

}

func lcs(x string, y string) int{
	var m = len(x)
	var n = len(y)

	c := make([][]int, m+1)
	for i:= range c{
		c[i] = make([]int, n+1)
	}
	for i:=	1;i<=m ;i++  {
		for j:=1;j<=n ;j++  {
			if x[i-1] == y[j-1]{
				c[i][j] = c[i-1][j-1] + 1
			}else{
				c[i][j] = int(math.Max(float64(c[i-1][j]), float64(c[i][j-1])))
			}


		}
	}
	return c[m][n]

}


func newReadString(ior io.Reader) func() string {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)

	return func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
}

func nint64() int64 {
	i, err := strconv.ParseInt(nstr(), 0, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func nint() int {
	return int(nint64())
}

func getIntSlice(n int) []int {
	b := make([]int, n)
	for i := 0; i < n; i++ {
		b[i] = nint()
	}
	return b
}

func getStringSlice(n int) []string {
	b := make([]string, n)
	for i := 0; i < n; i++ {
		b[i] = nstr()
	}
	return b
}

func gcd(x, y int) int {
	if y == 0 {
		return x
	}
	return gcd(y, x%y)
}

func lcm(x, y int) int {
	return x * y / gcd(x, y)
}

func contains(s []int, e int) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func bin(i int, prefix bool) string {
	i64 := int64(i)

	if prefix {
		return "0b" + strconv.FormatInt(i64, 2)
	} else {
		return strconv.FormatInt(i64, 2)
	}
}

func strReverse(s string) string {
	runes := []rune(s)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}

	return string(runes)
}

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;
  C[0][0] = 0;
  for ( int i = 1; 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]);
    }
  }javascript:void(0)

  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 <cmath>
#include <set>
#include <string>
#include <algorithm>
#include <vector>
#include <bitset>
#include <iomanip>
#include <map>

using std::cin;
using std::cout;
using std::endl;
using std::string;
using std::vector;
using std::bitset;

#define rep(i,n)    for(int i=0; i<(int)n; i++)
#define reps(i,s,e) for(int i=s; i<(int)e; i++)
typedef long double ld;
typedef long long ll;
typedef vector<int> vint;
typedef vector<ll> vll;
typedef std::pair<int, int> pii;
typedef std::pair<ll, ll> pll;

template<class T>
using Graph = vector<vector<T>>;

void printFixedDouble(double d, int fix) {
    cout << std::fixed;
    cout << std::setprecision(fix) << d << endl;
}

int main() {
    int datanum;
    cin >> datanum;
    rep(d, datanum) {
        string a, b;
        cin >> a >> b;

        int aLen = a.length();
        int bLen = b.length();

        int dp[aLen + 1][bLen + 1];
        rep(i, aLen + 1) {
            dp[i][0] = 0;
        }
        rep(i, bLen + 1) {
            dp[0][i] = 0;
        }

        rep(i, aLen) {
            rep(j, bLen) {
                if (a[i] == b[j]) {
                    dp[i+1][j+1] = std::max(std::max(dp[i+1][j], dp[i][j+1]), dp[i][j] + 1);
                } else {
                    dp[i+1][j+1] = std::max(dp[i+1][j], dp[i][j+1]);
                }
            }
        }

        cout << dp[aLen][bLen] << endl;
    }
}

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

using namespace std;
const int L = 1001;
const int INF = -1001001001;

int main()
{
    string s, t;
    int dp[L][L];
    int q;
    cin >> q;
    for(int i=0;i<q;++i)
    {
        cin >> s;
        cin >> t;
        for(int j=0;j<s.size()+1;++j) dp[j][0] = 0;
        for(int j=0;j<t.size()+1;++j) dp[0][j] = 0;
        for(int j=1;j<s.size()+1;++j)
        {
            for(int k=1;k<t.size()+1;++k)
            {
                if(s[j-1] == t[k-1])
                {
                    dp[j][k] = max(max(dp[j][k-1], dp[j-1][k-1] + 1), dp[j-1][k]);
                }
                else
                {
                    dp[j][k] = max(dp[j][k-1], dp[j-1][k]);
                }
            }
        }
        cout << dp[s.size()][t.size()] << endl;
    }
}

C++: #include <math.h>
#include <stdlib.h>
#include <algorithm>
#include <array>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

#define rep(i, n) for (int i = 0; i < (n); i++)
#define loop(i, a, n) for (int i = a; i < (n); i++)
#define all(in) in.begin(), in.end()
const int INF = 1e9;
const int MOD = 1e9 + 7;
#define MAX_q 150
#define MAX_L 1000
string X, Y;
int dp[MAX_L + 1][MAX_L + 1];
void DP() {
    rep(i, X.size()) {
        rep(k, Y.size()) { dp[i][k] = 0; }
    }
    rep(i, X.size()) {
        rep(k, Y.size()) {
            if (X[i] == Y[k]) {
                dp[i + 1][k + 1] = dp[i][k] + 1;
            } else {
                dp[i + 1][k + 1] = max(dp[i][k + 1], dp[i + 1][k]);
            }
        }
    }
}
int main() {
    int q;
    cin >> q;
    rep(j, q) {
        cin >> X >> Y;
        DP();
        cout << dp[X.size()][Y.size()] << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int dp[1001][1001];




	
int main (){
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	//input
	int n;
	cin >> n;
	vector<string> S(n);
	vector<string> T(n);
	for(int i=0;i<n;i++)cin >> S[i] >> T[i];


	//alorithm
	for(int i=0;i<n;i++){
		string s,t;
		s=S[i];
		t=T[i];
		memset(dp,0,sizeof(dp));
		for(int i=1;i<=s.size();i++){
			for(int j=1;j<=t.size();j++){
				if(s[i-1]==t[j-1]){dp[i][j]=dp[i-1][j-1]+1;continue;}
				dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
			}
		}
		cout << dp[s.size()][t.size()] << endl;
	}
}