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 <vector>
#include <algorithm>
using namespace std;


int main(){
  string X, Y;
  int q;
  cin >> q;
  for(int i = 0; i < q; i++){
    cin >> X >> Y;
    vector<vector<int> > dp(X.size(), vector<int>(Y.size(), 0));
    for(int i = 0; i < X.size(); i++){
      for(int j = 0; j < Y.size(); j++){
        if(X[i] == Y[j]){
          if(i == 0 || j == 0)dp[i][j] = 1;
          else dp[i][j] = dp[i - 1][j - 1] + 1;
        }else {
          if(i == 0 && j == 0)dp[i][j] = 0;
          else if(i == 0 && j != 0)dp[i][j] = dp[i][j - 1];
          else if(i != 0 && j == 0)dp[i][j] = dp[i - 1][j];
          else dp[i][j] = max(dp[i][j - 1], dp[i - 1][j]);
        }
      }
    }
    cout << dp[X.size() - 1][Y.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<iostream>
#include<cstdio>

using namespace std;

int maxa[1000];
int main(){
  int n;
  int k;
  int count;
  cin>>n;
  char X[1001];
  char Y[1001];
  for(int i=0;i<n;i++){
    cin>>X;
    cin>>Y;
    k=0;
    for(int a=0;X[a]!='\0';a++){
    count=0;
      for(int s=a;X[s]!='\0';s++){
	for(int j=k;Y[j]!='\0';j++){
	  if(X[s]==Y[j]){
	    count++;
	    k=j;
	    break;
	  }
	}
      }
      if(maxa[i]<count)maxa[i]=count;
    }
  }
  for(int i=0;i<n;i++){
    cout<<maxa[i]<<endl;
  }
  
  return 0;
}

C++: #define _GLIBCXX_DEBUG
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

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

int main() {
  int q;
  cin >> q;
  rep(k, q) {
    string x, y;
    cin >> x >> y;
    int m = x.size();
    int n = y.size();
    vector<vector<int> > dp(m + 1, vector<int>(n + 1, 0));
    rep(i, m) {
      rep(j, n) {
        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]);
        }
      }
    }
    cout << dp[m][n] << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <cstring>
#include <math.h>
#include <algorithm>
#include <vector>
#include <string>
#include <stdlib.h>
#include <queue>
#include <stack>
#include <utility>
#include <fstream>
#include <random>
#include <map>
#include <unordered_map>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n-1;i>=0;i--)
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ll long long
#define INF 1000000001
#define mod 1000000007
#define p pair<int,int>
int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};
using namespace std;
int POW(int x,int y){return int(pow(double(x),double(y)));}



int main(){
	int q;
	cin>>q;
	vector<string> s0(q),t0(q);
	rep(i,q){
		cin>>s0[i]>>t0[i];
	}
	rep(i,q){

	string s,t;
	s=s0[i];
	t=t0[i];
	vector<vector<int>> a(s.size());
	rep(i,s.size()){
		a[i].resize(t.size());
		rep(j,t.size()){
			if(i==0 && j==0){
				if(s[0]==t[0]) a[0][0]=1;
				else a[0][0]=0;
			}else if(j==0){
				if(s[i]==t[0]) a[i][0]=1;
				else a[i][0]=a[i-1][0];
			}else if(i==0){
				if(s[0]==t[j]) a[0][j]=1;
				else a[0][j]=a[0][j-1];
			}else{
				if(s[i]==t[j]) a[i][j]=a[i-1][j-1]+1;
				else a[i][j]=max(a[i][j-1],a[i-1][j]);
			}
		}
	}
	cout<<a[s.size()-1][t.size()-1]<<endl;
	}
}

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

int main(void){
    int q; cin >> q;
    int dp[1001][1001];
    for(int i = 0; i < 1001; i++) dp[0][i] = dp[i][0] = 0;

    for(int i = 0; i < q; i++){
        string a, b; cin >> a >> b;
        int len_a = (int)a.size(), len_b = (int)b.size();
        for(int j = 1; j <= len_a; j++){
            for(int k = 1; k <= len_b; k++){
                if(a[j-1]==b[k-1]) dp[j][k] = dp[j-1][k-1] + 1;
                else dp[j][k] = max(dp[j-1][k], dp[j][k-1]);
                // cout << "(j, k) = " << j << ", " << k << ": dp = " << dp[j][k] << '\n';
            }
        }

        cout << dp[len_a][len_b] << '\n';
    }

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define N 1050
int lc(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(){
  int n;cin>>n;
  while(n--){
    string s,v;cin>>s>>v;
    cout<<lc(s,v)<<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=0;i<=m;i++)
        c[i][0]=0;
  for(int j=0;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;
}