Go: package main

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

//Util
func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func maxInt(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func minInt(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

func absInt(a int) int {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func absFloat64(a float64) float64 {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func minFloat64(a, b float64) float64 {
	if a > b {
		return b
	} else {
		return a
	}
}

func str2Int(s string) int {
	n, _ := strconv.Atoi(s)
	return n
}

//Main
var sc = bufio.NewScanner(os.Stdin)
var q int
var X, Y string

func lcs(X, Y string) int {
	lenX := len(X)
	lenY := len(Y)
	dp := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		dp[i] = make([]int, lenY+1)
	}

	res := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if X[i-1] == Y[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
			//fmt.Println(dp)
			res = maxInt(res, dp[i][j])
		}

	}
	return res
}

func main() {
	sc.Split(bufio.ScanWords)
	q = nextInt()

	for i := 0; i < q; i++ {
		X = nextStr()
		Y = nextStr()

		fmt.Println(lcs(X, Y))
	}
}

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

static const int N = 1000;

int lcs(string X, string Y) {
    //DP memotable: c
    int c[N+1][N+1];
    int xSize = X.size();
    int ySize = Y.size();
    int maxl = 0;
    //first char will be empty because of dp table
    X = ' ' + X;
    Y = ' ' + Y;
    for (int i = 0; i <= xSize; i++) c[i][0] = 0;
    for (int j = 0; j <= ySize; j++) c[0][j] = 0;

    for (int i = 1; i <= xSize; i++) {
        for (int j = 1; j <= ySize; 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]);
        }
    }
    /*
    for (int i = 1; i <= xSize; i++) {
        for (int j = 1; j <= ySize; j++) {
            cout << c[i][j] << " ";
        }
        cout << endl;
    }
    */
    return maxl;
}

int main()
{
    int n; cin >> n;
    //string s1 = "abcbdab";
    //string s2 = "bdcaba";
    string s1, s2;
    for (int i = 0; i < n; i++) {
        cin >> s1 >> s2;
        cout << lcs(s1, s2) << endl;
    }
    return 0;
}

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

using namespace std;

string a,b;

int lcs(int i,int j){
  if(i==0 || j==0) return 0;
  if(a[i]==b[j]){
    return lcs(i-1,j-1)+1;
  }else{
    return max(lcs(i,j-1),lcs(i-1,j));
  }
}

int main(){
  int n; cin>>n;
  for(int i=0;i<n;i++){
    cin>>a>>b;
    a = ' ' + a;
    b = ' ' + b;
    cout<<lcs(a.size()-1,b.size()-1)<<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 = 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]);
    }
}
   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 <bits/stdc++.h>

#define int             long long
#define FOR( i, m, n )  for( int (i) = (m); (i) < (n); (i)++ )
#define REP( i, n )     FOR( i, 0, n )
#define REPR( i, m )    for( int (i) = (m); (i) >= 0; (i)-- )
#define REPONE( i, n )  FOR( i, 1, n + 1 )
#define ALL( a )        (a).begin(), (a).end()
#define MP              make_pair

using namespace std;
using P = pair<int, int>;

template<class T>bool chmax( T& a, const T& b ) { if( a < b ) { a = b; return 1; } return 0; }
template<class T>bool chmin( T& a, const T& b ) { if( a > b ) { a = b; return 1; } return 0; }

const int INF = 1e9;
const int MOD = 1e9 + 7;

int dp[1001][1001];

signed main(){
    int N; cin >> N;
    REP( i, N ){
        string s, t; cin >> s >> t;
        REP( i, s.size() ){
            REP( j, t.size() ){
                if( s[i] == t[j] ){
                    dp[i + 1][j + 1] = dp[i][j] + 1;
                }else{
                    dp[i + 1][j + 1] = max( dp[i + 1][j], dp[i][j + 1] );
                }
            }
        }

        cout << dp[s.size()][t.size()] << endl;
    }
}

C++: #include <stdio.h>
#include <vector>
#include <list>
#include <map>
#include <array>
#include <memory>
#include <string>
#include <iostream>
#include <sstream>
#include <algorithm>
#include <cmath>
#include <unordered_map>
#include <stdexcept>


using std::string;
using std::vector;


//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// util
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

std::vector<std::string> split(const std::string& input, char delimiter)
{
    std::istringstream stream(input);

    std::string field;
    std::vector<std::string> result;
    while (std::getline(stream, field, delimiter)) {
        result.push_back(field);
    }
    return result;
}



//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// user func
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

void printList(const vector<int>& list) {
    // print
    for(int i = 0; i < list.size(); i++){
        printf(" %d", list[i]);
    }
    printf("\n");
}



//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// logic
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

// Longest Common Subsequence
int LCS(const string& x, const string& y) {
    int result = 0;
    vector<vector<int>> table(x.length() + 1, vector<int>(y.length() + 1, 0));
    
    for (int i = 1; i <= x.length(); i++) {
        for (int j = 1; j <= y.length(); j++) {
            if (x[i-1] == y[j-1]) {
                table[i][j] += table[i-1][j-1] + 1;
            } else {
                table[i][j] = std::max(table[i-1][j], table[i][j-1]);
            }
            result = std::max(result, table[i][j]);
        }
    }
    return result;
}

void solve() {
    int n;
    scanf("%d", &n);
    for(int i = 0; i < n; i++){
        char bufX[1024];
        char bufY[1024];
        scanf("%s", bufX);
        scanf("%s", bufY);
        printf("%d\n", LCS(string(bufX), string(bufY)));
    }
}


//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// main
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
int main() {
    solve();
    return 0;
}