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 <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>
using namespace std;
#include <string>


int lcs(string x, string y){
  int m = x.size();
  int n = y.size();

  int c[1001][1001];
  for(int i=0;i<=m;i++) c[i][0] = 0;
  for(int j=0;j<=n;j++) c[0][j] = 0;

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

C++: #include <bits/stdc++.h>
#define REP(i, n) for(int i = 0; i < (n); ++i)
using namespace std;

static const int N = 1000;

int LCS(string x, string y) {
    int c[N + 1][N + 1];
    int n = x.length();
    int m = y.length();
    int maxl = 0;
    x = ' ' + x;
    y = ' ' + y;

    REP(i, n) c[i][0] = 0;
    REP(i, m) c[0][i] = 0;
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; j++) {
            if(x[i] == y[j]) {
                c[i][j] = c[i - 1][j - 1] + 1;
            } else {
                c[i][j] = max(c[i][j - 1], c[i - 1][j]);
            }
            maxl = max(c[i][j], maxl);
        }
    }

    return maxl;
}

int soraLCS(string x, string y) {
    int n = x.length();
    int m = y.length();
    x = ' ' + x;
    y = ' ' + y;
    int c[N + 1][N + 1];
    REP(i, n) c[i][0] = 0;
    REP(i, m) c[0][i] = 0;

    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; 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]);
            }
        }
    }
    return c[n][m];
}

int main() {
    int q;
    string X, Y;

    cin >> q;
    REP(i, q) {
        cin >> X >> Y;
        cout << soraLCS(X, Y) << endl;
    }
    return 0;
}

C++: #include <cstdio>
#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;
const int MAX_Q = 150, MAX_X = 1000;
int q, dp[MAX_X + 1][MAX_X + 1];
string x[MAX_X], y[MAX_X];

void solve() {
    for (int i = 0; i < q; i++) {
        for (int j = 0; j < x[i].length(); j++) {
            for (int k = 0; k < y[i].length(); k++) {
                if (x[i][j] == y[i][k]) {
                    dp[j + 1][k + 1] = dp[j][k] + 1;
                } else {
                    dp[j + 1][k + 1] = max(dp[j][k + 1], dp[j + 1][k]);
                }
            }
        }
        cout << dp[x[i].length()][y[i].length()] << endl;
    }
}

int main() {
    cin >> q;
    for (int i = 0; i < q; i++) {
        cin >> x[i] >> y[i];
    }
    solve();
    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++: //Longest Common Subsequence
#include<iostream>
#include<algorithm>
#include<string>
using namespace std;
#define REP(i, limit) for(int i=0; i< limit; ++i)
#define LINT long long

int main(){
  int q;
  string X, Y;
  int dp[1001][1001]={};
  int m, n;
  int ans;


  cin >> q;
  REP(s, q){
    dp[1001][1001]={};
    cin >> X >> Y;
    m=X.size();
    n=Y.size();
    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>
using namespace std;
int lcs(string a,string b)
{
    if(a.length()<=0||b.length()<=0)
    {
        return 0;
    }
    else if(a[a.length()-1]==b[b.length()-1])
    {
        return 1+lcs(a.substr(0,a.length()-1),b.substr(0,b.length()-1));
    }
    else
    {
        return max(lcs(a.substr(0,a.length()),b.substr(0,b.length()-1)),lcs(a.substr(0,a.length()-1),b.substr(0,b.length())));
    }
};
int main()
{
    int num;
    cin>>num;
    for(int i=0;i<num;i++)
    {
        string a,b;
        cin>>a>>b;
        cout<<lcs(a,b)<<endl;
    }
}

C++: #include <bits/stdc++.h>
using ll = long long;
using namespace std;
#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for(int i = int(a); i < int(b); ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
const long long INFLL = 1LL << 60;
const int INFINT = 1 << 30;
const long long MOD = 1e9 + 7;

template <class T> void vecout(T V) {
    auto t = V.begin();
    *t++;
    while(t != V.end()) {
        cout << " " << *t++;
        // if(t != V.end()) cout << " ";
    }
    cout << endl;
};
vector<vector<int>> dp(1001, vector<int>(1001));

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int Q;
    string S, T;
    cin >> Q;
    rep(q, Q) {
        cin >> S >> T;
        dp.assign(S.size() + 1, vector<int>(T.size() + 1, 0));
        rep(i, 0, S.size()) {
            rep(j, 0, T.size()) {
                if(S.at(i) == T.at(j)) {
                    dp.at(i + 1).at(j + 1) = dp.at(i).at(j) + 1;
                } else {
                    dp.at(i + 1).at(j + 1) =
                        max(dp.at(i + 1).at(j), dp.at(i).at(j + 1));
                }
            }
        }
        cout << dp.at(S.size()).at(T.size()) << endl;
    }
}