Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	resolve()
}

func resolve() {
	n := scanInt(sc)
	results := []int{}
	for i := 0; i < n; i++ {
		results = append(results, resolveInstance())
	}
	for _, v := range results {
		fmt.Println(v)
	}
	return
}

func resolveInstance() int {
	x, y := scanString(sc), scanString(sc)
	lx, ly := len(x), len(y)
	dp := make([][]int, lx+1)
	dp[0] = make([]int, ly+1)
	for i := 1; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
		dp[i][0] = dp[i-1][0]
		for j := 1; j <= ly; j++ {
			dp[i][j] = dp[i-1][j]
			if dp[i][j] < dp[i][j-1] {
				dp[i][j] = dp[i][j-1]
			}
			if x[i-1] == y[j-1] {
				cL := dp[i-1][j-1] + 1
				if dp[i][j] < cL {
					dp[i][j] = cL
				}
			}
		}
	}
	return dp[lx][ly]
}

const (
	remove = 0 + iota
	match
)

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include "bits/stdc++.h"

#define REP(i,num) for(ll i=0;i<(num);++i)
#define LOOP(i) while(i--)
#define ALL(c) c.begin(),c.end()
#define PRINTALL(c) for(auto pitr=c.begin();pitr!=c.end();++pitr){cout<<*pitr;if(next(pitr,1)!=c.end())cout<<' ';}cout<<endl;
#define PAIRCOMP(c,comp) [](const pair<ll,ll>& lhs,const pair<ll,ll>& rhs){return lhs.c comp rhs.c;}

using namespace std;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;

constexpr ll atcoder_mod = 1e9+7;

template<typename T=ll>
T in(){T x; cin >> x; return (x);}
template<typename T=ll,typename C=vector<T>>
C vecin(int N){C x(N);REP(i,N){x[i]=in<T>();}return move(x);}

void vout(){cout << endl;}
template<typename Head,typename... Tail>
void vout(Head&& h,Tail&&... t){cout << ' ' << h;vout(forward<Tail>(t)...);}
void out(){cout << endl;}
template<typename Head,typename... Tail>
void out(Head&& h,Tail&&... t){cout << h;vout(forward<Tail>(t)...);}

template<typename T>
bool chmax(T& a,T b){if(a<b){a=b;return true;}return false;}
template<typename T>
bool chmin(T& a,T b){if(a>b){a=b;return true;}return false;}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);

	int N=in();
	LOOP(N){
		string S=in<string>(),T=in<string>();
		int LS=S.size(),LT=T.size();
		vvll dp(LS+1,vll(LT+1,0));
		REP(i,LS){
			REP(j,LT){
				if(S[i]==T[j]){
					chmax(dp[i+1][j+1],max({dp[i+1][j],min(dp[i][j]+1,j+1)}));
				}
				else{
					chmax(dp[i+1][j+1],max({dp[i+1][j],dp[i][j+1]}));
				}
			}
		}
		out(dp[LS][LT]);
	}
	
	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++){
    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] = mx(c[i - 1][j], c[i][j = 1]);
      }
      maxl = max(mxl, 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 << lcs8s1, s2) << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <algorithm>
using namespace std;

int lcs(char X[], char Y[]) {
    int m = strlen(X);
    int n = strlen(Y);
    int C[1001][1001];
    int maxl = 0;
    
    for (int i = 0; i <= m; i++) { C[i][0] = 0; }
    for (int i = 1; i <= n; i++) { C[0][i] = 0; }
    
    for (int i = 1; i <= m; i++) {
        for (int j = 1; j <= n; j++) {
            if (X[i-1] == Y[j-1]) {
                C[i][j] = C[i - 1][j - 1] + 1;
            } else if (C[i - 1][j] >= C[i][j - 1]) {
                C[i][j] = C[i - 1][j];
            } else {
                C[i][j] = C[i][j - 1];
            }
            
            maxl = max(maxl, C[i][j]);
        }
    }
    
    return maxl;
}

int main() {
    int N;
    scanf("%d", &N);
    
    for (int i = 0; i < N; i++) {
        char X[1000], Y[1000];
        scanf("%s", X);
        scanf("%s", Y);
        cout << lcs(X, Y) << 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; // X[0] に空白を挿入
	Y = ' ' + Y; // Y[0] に空白を挿入
	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<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 <sstream>
#include <cstdio>
#include <stdlib.h>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
#define max 1001
int n,c[max][max];
string x,y;
void SerchMinStr(){
  int i,j,ans,k;
  for(i=1;i<(int)x.length()+1;i++){
    for(j=1;j<(int)y.length()+1;j++){
      if(x[i-1]==y[j-1]){c[i][j]=c[i-1][j-1]+1;}
      else if(c[i-1][j]>=c[i][j-1])c[i][j]=c[i-1][j];
      else c[i][j]=c[i][j-1];
    }
  }
  i--;j--;
  ans=c[i][j];

  for(k=1;k<(int)x.length();k++)
    if(ans<c[k][j])ans=c[k][j];
  for(k=1;k<(int)y.length();k++)
    if(ans<c[i][k])ans=c[i][k];
  cout<<ans<<endl;
}
int main(){
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>x>>y;
    SerchMinStr();
  }  
  return 0;
}