Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	Q := sc.nextInt()
	for q := 0; q < Q; q++ {
		X, Y := sc.nextStr(), sc.nextStr()
		xLen, yLen := len(X), len(Y)
		dp := make([][]int, xLen+1)
		for i := 0; i <= xLen; i++ {
			dp[i] = make([]int, yLen+1)
		}
		for x := 0; x <= xLen; x++ {
			for y := 0; y <= yLen; y++ {
				if x == 0 || y == 0 {
					dp[x][y] = 0
				} else if X[x-1] == Y[y-1] {
					dp[x][y] = dp[x-1][y-1] + 1
				} else {
					dp[x][y] = max(dp[x-1][y], dp[x][y-1])
				}
			}
		}
		fmt.Fprintln(wtr, dp[xLen][yLen])
	}

	wtr.Flush()
}

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 = 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]);
		}
	}

	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 <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 = 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]);
    }
  }

  return maxl;
}

int main() {
  string s1, s2;
  int q;
  cin >> q;

  for ( int i = 0; i < q; i++ ) {
    cin >> s1 >> s2;
    cout << lcs(s1, s2) << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
using namespace std;
const int MAX=1001;
int lcs(string X,string Y) {
    int i=0,j=0,c[MAX][MAX],x=X.length(),y=Y.length();
    for(i=0;i<=x;i++)c[i][0]=0;
    for(i=0;i<=y;i++)c[0][i]=0;
    for(i=1;i<=x;i++) 
        for(j=1;j<=y;j++) 
            if(X[i-1]==Y[j-1])c[i][j]=c[i-1][j-1]+1; 
            else c[i][j]=max(c[i][j-1],c[i-1][j]);
    /*cout<<"???????????????????????????????????????"<<endl;
    for(i=1;i<=x;i++){
        for(j=1;j<=y;j++)cout<<c[i][j]<<" ";
        cout<<endl;
    }*/
    return c[x][y];
}
int main(){
    int n;cin>>n;
    string X,Y;
    while(n--){
        cin>>X>>Y;
        cout<<lcs(X,Y)<<endl;
    }
}

C++: #include <iostream>
#include <string>
#include <algorithm>
    using namespace std;
int lcs(string x,string y){
    int c[1010][1010];
    int m = x.size();
    int n = y.size();
    int maxl=0;
    x = ' '+x;
    y = ' '+y;
    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]);
        }
        
    }
    return maxl;
}
int main(){
    int q;
    string x;
    string y;
    scanf("%d",&q);
    for (int i=0; i<q; i++) {
        cin>>x>>y;
        cout<<lcs(x, y)<<endl;
    }
    return 0;
}

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

using namespace std;


using ll = long long;


ll c[1001][1001];
void solve()
{
    string X, Y;
    cin >> X >> Y;

    memset(c, 0, sizeof(c));
    for (ll i = 0; i <= X.length(); i++)
        c[i][0] = 0;
    for (ll i = 0; i <= Y.length(); i++)
        c[0][i] = 0;

    for (ll i = 1; i <= X.length(); i++) {
        for (ll j = 1; j <= Y.length(); j++) {
            if (X[i - 1] == Y[j - 1]) {
                c[i][j] = c[i - 1][j - 1] + 1;
            } else {
                c[i][j] = max(c[i - 1][j], c[i][j - 1]);
            }
        }
    }

    cout << c[X.length()][Y.length()] << endl;
}


int main()
{
    ll q;
    ll c[151][151];

    cin >> q;
    for (ll i = 0; i < q; i++) {
        solve();
    }
}

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

const int length = 1005;
int dp[length][length];

void LCS(std::string X, std::string Y)
{
  auto m = X.length();
  auto n = Y.length();


  for (int i=0; i<m; ++i)
    dp[i][0] = 0;
  for (int j=1; j<n; ++j)
    dp[0][j] = 0;

  for (int i=1; i<=m; ++i)
    {
      for (int j=1; j<=n; ++j)
        {
          if (X[i-1] == Y[j-1])
            dp[i][j] = dp[i-1][j-1] + 1;
          else
            {
              dp[i][j] = std::max(dp[i-1][j], dp[i][j-1]);
            }
        }
    }
}

int main ()
{
  int q;
  std::cin >> q;

  std::string X, Y;
  for (int i=0; i<q; ++i)
    {
      std::cin >> X >> Y;
      LCS(X, Y);
      std::cout << dp[X.length()][Y.length()] << std::endl;
    }
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cassert>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define rep(i,n) FOR(i,0,n)
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define vint vector<int>
#define vdouble vector<double>
#define vstring vector<string>
using namespace std;

#include<map>
#include<set>
#include<queue>

typedef long long ll;
typedef unsigned long long ull;

const int MAX_N = 1000000;

int NN;
string s1, s2;
int dp[1001][1001];

int run(){
	int N1 = s1.length();
	int N2 = s2.length();
	
	rep(i1, N1+1)
	rep(i2, N2+1){
		if(i1 == 0 || i2 == 0) dp[i1][i2] = 0;
		else{
			if(s1[i1-1] == s2[i2-1]) dp[i1][i2] = dp[i1-1][i2-1] + 1;
			else dp[i1][i2] = max(dp[i1-1][i2], dp[i1][i2-2]);
		}
	}
	return dp[N1][N2];
}

int main() {
	cin >> NN;
	rep(i, NN){
		cin >> s1;
		cin >> s2;
		cout << run() << endl;
	}
}