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++: 
#define REP(i, t, n)  for (int i = t; i < n; i++)
#define ALL(n)        (n).begin(),(n).end()
#include <limits.h>
#include <stdio.h>
#include <cmath>
#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <map>
#include <queue>
#include <deque>
#include <functional>
#include <algorithm>
#include <cstring>
#include <unordered_map>
#include <numeric>

using namespace std;

typedef bool               BOOL;
typedef short              WORD;
typedef unsigned short     U_WORD;
typedef long               DWORD;
typedef unsigned long      U_DWORD;
typedef long long          QWORD;
typedef unsigned long long U_QWORD;

#define LEN_MAX (1000)
DWORD dpLCS[LEN_MAX + 1][LEN_MAX + 1];

void initDpTable(DWORD maxI, DWORD maxJ)
{
	REP(i, 0, maxI + 1) {
		REP(j, 0, maxJ + 1) {
			dpLCS[i][j] = 0;
		}
	}

}

void solve_main()
{
	DWORD dwNum;
	string str1, str2;
	cin >> dwNum;
	REP(loop, 0, dwNum) {
		cin >> str1;
		cin >> str2;
		initDpTable(str1.length(), str2.length());

		REP(i, 1, (str1.length() + 1)) {
			REP(j, 1, (str2.length() + 1)) {
				if (str1[i - 1] == str2[j - 1]) {
					dpLCS[i][j] = dpLCS[i - 1] [j - 1] + 1;
				} else {
					dpLCS[i][j] = max(dpLCS[i - 1][j], dpLCS[i][j - 1]);
				}
			}
		}
		cout << dpLCS[str1.length()][str2.length()] << endl;
	}
}

int main()
{
#ifdef FOR_IDE
	ifstream in("input.txt");
	cin.rdbuf(in.rdbuf());
#endif

	solve_main();
	return 0;
}

C++: //   _/                _/                 _/_/_/   _/
//_/_/_/_/   _/_/   _/_/_/_/   _/_/    _/       _/_/
// _/     _/    _/   _/     _/    _/  _/_/_/     _/
//_/     _/    _/   _/     _/    _/  _/    _/   _/
// _/_/   _/_/       _/_/   _/_/      _/_/     _/
#include<iostream>
#include<algorithm>
#include<cmath>
#include<iomanip>
#include<set>
#include<map>
#include<queue>
#include<vector>
#include<random>
using namespace std;
typedef long long ll;
const int MOD=1e9+7;
const double pi=3.14159265358979323846;
const int inf=1e9;
const ll INF=1e18;
int main() {
  cin.tie(0),cout.tie(0);
  ios::sync_with_stdio(false);
  int q;
  cin >> q;
  while(q--) {
    string s,t;
    cin >> s >> t;
    int dp[s.size()+5][t.size()+5]={};
    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;
        }
        else {
          dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
        }
      }
    }
    cout << dp[s.size()][t.size()] << endl;
  }
 }

C++: #include <iostream>
#include <string>
using namespace std;
static const int MAX = 1001;

void lcs(string X, string Y) {
	int dp[MAX][MAX];  
	int i,j;

	int xLength = X.size();
	int yLength = Y.size();


	// initialize dp[][]
	for (i = 1; i <= xLength; i++)
		dp[i][0] = 0;
	for (i = 1; i <= yLength; i++)
		dp[0][i] = 0;

	for (i = 1; i <= xLength; i++){
		for (j = 1; j <= yLength; j++){
			// Because the original string is 0-based , so subtracted from 1
			if (X[i - 1] == Y[j - 1]) {
				dp[i][j] = dp[i-1][j-1] + 1;
			}else {
				dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
			}
		}
	}

	// testing code: print out the dp[][]
	cout << "j";
	for (j = 1; j <= yLength; j++)
		cout << ' ' << j ;
	cout << endl;
		

	for (i = 1; i <= xLength; i++){
		cout << i << '.';
		for (j = 1; j <= yLength; j++){
			cout << dp[i][j] << ' ';
		}
		cout << endl;
	}

	cout << dp[xLength][yLength] << endl;
}

int main() {
	int n , i;
	string X, Y;

	cin >> n;
	for (i = 0 ; i < n; i++ ) {
		cin >> X;
		cin >> Y;
		lcs(X, Y);
	}

	return 0;

}

C++: 
#include<bits/stdc++.h>
using namespace std;
#define mx 1007
string a,b;
int dp[mx][mx];
bool visited[mx][mx];

void init(int n)
{
    for(int i=0;i<n;i++)
    for(int j=0;j<n;j++)
    {
        visited[i][j]=false;
    }
}

int lcs(int i,int j)
{
    if(i==a.size() || j==b.size())
    {
        return 0;
    }

    if(visited[i][j])return dp[i][j];

    int ans=0;
    if(a[i]==b[j])
        ans=1+lcs(i+1,j+1);
    else ans+=max(lcs(i+1,j),lcs(i,j+1));

    dp[i][j]=ans;
    visited[i][j]=true;
    return dp[i][j];
}

int main()
{


 int n;
 cin>>n;
 while(n--)
 {
     cin>>a>>b;
     init(max(a.size(),b.size()));
     cout<<lcs(0,0)<<endl;
 }






    return 0;
}

C++: #include<math.h>
#include<limits.h>
#include<iostream>
#include<string>
#include<vector>
#include<stdio.h>
#include<sstream>
#include<list>
#include<queue>
#include<algorithm>
#include<functional>
#include<map>
#include<set>
//#include<utility>
//#include<initializer_list>
//#include<tuple>
//#include<regex>
using namespace std;
#define ull unsigned long long
#define ll long long
#define rep(i, n) for(int i=0;i<(int)(n);i++)
#define all(t) t.begin(), t.end()
bool isSubstring(string substr, string t) {
	int n = substr.length();
	int seek = 0;
	rep(i, n) {
		bool ex = 0;
		for (int j = seek; j < t.length(); j++) {
			if (substr[i] == t[j]) {
				ex = 1;
				seek = j + 1;
				break;
			}
		}
		if (ex) {
			continue;
		}
		else {
			return false;
		}
	}
	return true;

}

int LongestCommonSubstring(string s, string t) {
	vector<int>dp(s.length(), 0);
	int n = s.length();
	string lcs = "";
	if (isSubstring(s.substr(n - 1, n), t)) {

		dp[n - 1] = 1;
		lcs = s[n - 1];
	}
	for (int i = n - 2; i >= 0; i--) {
		//string substr = s.substr(i, n);
		string substr = s[i] + lcs;
		int issubst = isSubstring(substr, t);
		if (issubst) lcs = substr;
		dp[i] = dp[i + 1] + issubst;
	}
	return dp[0];
}
int main() {
	//cout << isSubstring("abc", "abcde") << endl;
	//cout << isSubstring("bd", "abcde") << endl;
	//cout << isSubstring("db", "abcde") << endl;

	//cout << LongestCommonSubstring("bacd", "becd") << endl;
	//cout << LongestCommonSubstring("abcd", "becd") << endl;
	int q;
	cin >> q;
	vector<string> s(q);
	vector<string> t(q);
	rep(i, q) {
		cin >> s[i] >> t[i];
	}
	rep(i, q) {
		cout << LongestCommonSubstring(s[i], t[i]) << endl;
	}

	return 0;
}