Go: package main

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

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

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

func lcs(a, b string) int {
	lenA := len(a)
	lenB := len(b)
	dp := make([][]int, lenA+1)
	for i := range dp {
		dp[i] = make([]int, lenB+1)
	}

	for i := 1; i <= lenA; i++ {
		for j := 1; j <= lenB; j++ {
			if a[i-1] == b[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = max(dp[i][j-1], dp[i-1][j])
			}
		}
	}
	return dp[lenA][lenB]
}

func main() {
	n := scanInt()
	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		a := scanString()
		b := scanString()
		fmt.Fprintln(w, lcs(a, b))
	}
	w.Flush()
}

C++: #include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i)
#define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i)
#define each(a,b) for(auto& (a): (b))
#define all(v) (v).begin(),(v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define cmx(x,y) x=max(x,y)
#define cmn(x,y) x=min(x,y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define spair(p) cout<<#p<<": "<<p.fi<<" "<<p.se<<endl
#define sar(a,n) cout<<#a<<":";rep(pachico,n)cout<<" "<<a[pachico];cout<<endl
#define svec(v) cout<<#v<<":";rep(pachico,v.size())cout<<" "<<v[pachico];cout<<endl
#define svecp(v) cout<<#v<<":";each(pachico,v)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl
#define sset(s) cout<<#s<<":";each(pachico,s)cout<<" "<<pachico;cout<<endl
#define smap(m) cout<<#m<<":";each(pachico,m)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl

using namespace std;

typedef pair<int,int> P;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

const int MAX_SIZE = 52;

int LCS(const string& a, const string& b){
    int n = (int)a.size(), m = (int)b.size();
    vector<int> x(n), y(m);
    rep(i,n){
        x[i] = a[i]-'a';
        if(x[i] < 0){
            x[i] = a[i]-'A'+26;
        }
    }
    rep(i,m){
        y[i] = b[i]-'a';
        if(y[i] < 0){
            y[i] = b[i]-'A'+26;
        }
    }
    vector<vector<int> > vec(MAX_SIZE);
    for(int j = m-1; j >= 0; --j){
        vec[y[j]].push_back(j);
    }
    vector<int> xs(n, INF);
    rep(i,n){
        rep(j,(int)vec[x[i]].size()){
            *lower_bound(xs.begin(),xs.end(),vec[x[i]][j]) = vec[x[i]][j];
        }
    }
    return lower_bound(xs.begin(),xs.end(),INF) - xs.begin();
}


int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int q;
    cin >> q;
    rep(i,q){
        string a,b;
        cin >> a >> b;
        cout << LCS(a,b) << "\n";
    }
    return 0;
}

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

int lcs(char X[], char Y[])
{
	int C[1001][1001];
	int m = strlen(X);
	int n = strlen(Y);
	int maxl = 0;

	for (int i = 1; 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] == 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()
{
	ios::sync_with_stdio(false);
	cin.tie(0);

	char N1[1000], N2[1000];
	int q;

	cin >> q;
	for (int i = 0; i < q; i++)
	{
		cin >> N1 >> N2;
		cout << lcs(N1, N2);
	}
		
	return 0;                                                                            
}

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

int lcs(string a,string b){
    if(a.size()==0 || b.size()==0) return 0;
    int alen = a.size();
    int blen = b.size();
    vector<vector<int>> dp(alen,vector<int>(blen,0));
    dp[0][0] = a[0] == b[0]? 1:0;
    for(int j = 1; j<blen;j++) dp[0][j] = a[0]==b[j]? 1:dp[0][j-1];
    for(int i = 1; i<alen;i++) dp[i][0] = a[i]==b[0]? 1:dp[i-1][0];
    for(int i = 1;i<alen;i++){
        for(int j=1;j<blen;j++){
            dp[i][j] = dp[i-1][j-1];
            if(a[i]==b[j]) dp[i][j]++;
            dp[i][j] = max(dp[i][j],max(dp[i-1][j],dp[i][j-1]));
        }
    }
    return dp[alen-1][blen-1];
}

int main(){
    //string a = "a";
    //string b = "c";
    int p;
    cin >> p;
    for(int i = 0;i<p;i++){
        string a,b;
        cin >> a >> b;
        cout << lcs(a,b) << 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=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;
    }
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<map>
#include<set>
#include<cstdio>
#include<cmath>
#include<numeric>
#include<queue>
#include<stack>
#include<cstring>
#define repp(i,a,b) for(int i=(int)a;i<(int)b;++i)
#define repm(i,a,b) for(int i=(int)a;i>(int)b;--i)
typedef long long ll;
static const ll mod = 1e9 + 7;
static const ll INF = 1LL << 50;
using namespace std;


string x, y;
ll c[1005][1005];

ll lcs(ll m, ll n) {
	ll maxv = 0;
	for (int i = 0; i <m; ++i) {
		for (int j = 0; j <n; ++j) {
			if (x[i] == y[j])c[i+1][j+1] = c[i][j] + 1;
			else c[i+1][j+1] = max(c[i][j+1], c[i+1][j]);
			maxv = max(maxv, c[i+1][j+1]);
		}
	}
	return maxv;
}

int main() {
	int q;
	cin >> q;
	vector<ll>ans(q);
	repp(i, 0, q) {
		cin >> x >> y;
		ll m = x.size(), n = y.size();
		memset(c, 0, sizeof(c));
		ans[i] = lcs(m, n);
	}
	for (int i = 0; i < q;++i)cout << ans[i] << 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 i,j;
  int maxl=0;
  X= ' ' + X;
  Y= ' ' + Y;
 
  for(i=1;i<=m;i++) c[i][0]=0;
  for(j=1;j<=n;j++) c[0][j]=0;

  for(i=1;i<=m;i++){
    for(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;
}