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>
using namespace std;
#define rep(i, n) for (int i=0; i < (int)(n); i++)
using ull = unsigned long long;
using ll = long long;

int dp[1010][1010];

void LCS(string X, string Y) {
    rep(i, X.size()+1) rep(j, Y.size()+1) dp[i][j] = 0;

    rep(i, X.size()) rep(j, Y.size()) {
        if (X[i] == Y[j]) dp[i+1][j+1] = max({dp[i][j]+1, dp[i][j+1], dp[i+1][j]});
        else dp[i+1][j+1] = max({dp[i][j], dp[i][j+1], dp[i+1][j]});
    }

    cout << dp[X.size()][Y.size()] << endl;
}


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

    rep(i, q) {
        string x, y;
        cin >> x >> y;

        LCS(x, y);
    }

    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]c[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)<<enl;
  }
  return 0;
}

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

int main(void){
	int q;
	string a,b;
	cin>>q;
	while(q--){
		cin>>a>>b;
		int dp[1010][1010] = {0};
		for(int j = 0 ; j < a.size() ; j ++){
			for(int i = 0 ; i < b.size() ; i ++){
				if(a[j] == b[i]){
					dp[j+1][i+1] = dp[j][i]+ 1;
				}else{
					dp[j+1][i+1] = max(dp[j][i+1],dp[j+1][i]);
				}
			}
		}
		cout<<dp[a.size()][b.size()]<<endl;
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
#define repd(i,a,b) for (int i=(a);i<(b);i++)
#define rep(i,n) repd(i,0,n)
#define all(x) (x).begin(),(x).end()
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
typedef long long ll;
const long long INF = 1LL << 60;
typedef pair<int, int> P;
int dp[1001][1001];
int main()
{
    int q;
    cin >> q;
    rep(i, q) {
        string A, B;
        cin >> A >> B;
        rep(i, A.size()) {
            rep(j, B.size()) {
                dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
                if (A[i] == B[j]) chmax(dp[i + 1][j + 1], dp[i][j] + 1);
            }
        }
        cout << dp[(int)A.size()][(int)B.size()] << endl;
    }
    return 0;
}

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

using namespace std;

int lcs(string a, string b)
{
	vector<vector<int> > dp(1001, vector<int>(1001));
	for (int i = 0; i < a.size(); ++i)
	{
		for (int j = 0; j < b.size(); ++j)
		{
			if (a[i] == b[j])
			{
				dp[i + 1][j + 1] = dp[i][j] + 1;
			}
			else
			{
				dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
			}
		}
	}
	return(dp[a.size()][b.size()]);
}

void solve()
{
	int q;
	cin >> q;
	for (int i = 0; i < q; ++i)
	{
		string a, b;
		cin >> a >> b;
		cout << lcs(a, b) << endl;
	}
}

int main()
{
	solve();
	return(0);
}

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

using namespace std;

int LCS(string X, string Y) {

	int lcs[X.size() + 1][Y.size() + 1];

	for (int i = 0; i < X.size(); ++i) {
		lcs[0][i] = 0;
	}
	for (int i = 0; i < Y.size(); ++i) {
		lcs[i][0] = 0;
	}

	for (int i = 1; i <= X.size(); ++i) {
		for (int j = 1; j <= Y.size(); ++j) {
			if (X[i - 1] == Y[j - 1]) {
				lcs[i][j] = lcs[i - 1][j - 1] + 1;
			} else if (lcs[i - 1][j] > lcs[i][j - 1]) {
				lcs[i][j] = lcs[i - 1][j];
			} else {
				lcs[i][j] = lcs[i][j - 1];
			}
		}
	}

	return lcs[X.size()][Y.size()];
}

int main() {

	int q;
	scanf("%d", &q);

	for (int i = 0; i < q; ++i) {
		string X, Y;
		cin >> X >> Y;
		cout << LCS(X, Y) << endl;
	}

	return 0;

}

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

using namespace std;


int solve(const string& s1, const string& s2) {
    const size_t N = 1000 + 1;
    int A[N][N] = {0};

    auto m = s1.size();
    auto n = s2.size();
    for (int i = 1; i <= m; ++i) {
        for (int j = 1; j <= n; ++j) {
            if (s1[i-1] == s2[j-1]) {
                A[i][j] = A[i-1][j-1] + 1;
            } else {
                A[i][j] = max(A[i][j-1], A[i-1][j]);
            }
        }
    }
    return A[m][n];
}

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

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

    return 0;
}

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

using namespace std;

#if 0

以下のURLを参照。参照した箇所は、a = ' ' + a;のように空白をいれていることで文字のサイズを合わせていることである。
http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=2065462#1

サンプルインプットでは正しい出力を得られているようにみられているが、なぜかwrong answerが出力されてしまう。
#endif

int n;
string a, b;



int main(){
  cin >> n;
  while(n != 0){
    n = n -1;
    int longest[1051][1051];
    cin >> a;
    cin >> b;
    //a = ' ' + a;
    //b = ' ' + b;
    for(int i = 0; i <= a.size(); ++i){
      for(int j = 0; j <= b.size(); ++j){
        if(j <= 0 || i <= 0){
          longest[i][j] = 0;
        }
        else if(a[i] == b[j]){
          longest[i][j] = 1 + longest[i-1][j - 1];
        }
        else{
          longest[i][j] = max(longest[i][j-1], longest[i-1][j]);
        }
        
      }
    }
    //cout << a[1] << endl;
    cout << longest[a.size()][b.size()] << endl;
  }
}

C++: #include <cstdio>
#include <cstdlib>
#include <string>
#include <iostream>

using namespace std;
static const int N=1000;
int lcs(string X, string Y){
    int m=X.size();
    int n=Y.size();
    int c[N+1][N+1];
    int maxl=0;
    X=' '+X;
    Y=' '+Y;
    int i,j;
    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][j-1],c[i-1][j]);
            }
            maxl=max(maxl,c[i][j]);
        }
    }
    return maxl;
}
int main()
{
    int n;
    string s1,s2;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>s1>>s2;
        cout<<lcs(s1,s2)<<endl;
    }

    return 0;
}