Go: package main

/*
最長共通部分列
*/

import (
	"bufio"
	"bytes"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func larger(l, r int) int {
	if l > r {
		return l
	}
	return r
}

var memo [1001][1001]int

func countLCS(x, y string) int {
	x = " " + x
	y = " " + y
	max := 0
	for xi := 1; xi < len(x); xi++ {
		for yi := 1; yi < len(y); yi++ {
			if x[xi] == y[yi] {
				memo[xi][yi] = memo[xi-1][yi-1] + 1
			} else {
				memo[xi][yi] = larger(memo[xi-1][yi], memo[xi][yi-1])
			}
			max = larger(max, memo[xi][yi])
		}
	}
	return max
}

func main() {
	scanner := makeScanner(1024)
	q := eGetInt(scanner)
	for i := 0; i < q; i++ {
		x := eGetLine(scanner)
		y := eGetLine(scanner)
		fmt.Println(countLCS(x, y))
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}
func min(a []int) int {
	m := a[0]
	for _, v := range a {
		if v < m {
			m = v
		}
	}
	return m
}

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

C++: #include <bits/stdc++.h>
using namespace std;
#define r(i,n) for(auto i=0;i<n;i++)
#define s(c) static_cast<int>((c).size())

int dp[1001][1001];
int main(){
	int n = 0;
	cin >> n;
	int x, y;
	string X, Y;
	r(k, n){
		cin >> X >> Y;
		x = X.length();
		y = Y.length();
		r(i, x+1)
			r(j, y+1)
				dp[i][j] = 0;

		r(i, x){
			r(j, y){
				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{
						dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
					}
				}

			}
		}
		cout << dp[x-1][y-1] << 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;

    for(int a=0;X[a]!='\0';a++){
    count=0;
    k=0;
      for(int s=a;X[s]!='\0';s++){
	for(int j=k;Y[j]!='\0';j++){
	  if(X[s]==Y[j]){
	    //	    cout<<X[s];
	    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++: #include <string>
#include <iostream>
using namespace std;

int n;
string x, y;
bool mat[1000][1000];
int a[1000][1000];

int max(int i, int j) {
	int r = (!mat[i - 1][j] ? a[i - 1][j] : 0);
	r = ((!mat[i][j - 1] && a[i][j - 1] > r) ? a[i][j - 1] : r);
	return r > a[i - 1][j - 1] ? r : a[i - 1][j - 1];
}

int main(){
	cin >> n;
	for (int ia = 0; ia < n; ia++) {
		int ans = 0, p = 0;
		cin >> x >> y;
		for (int i = 0; i < x.length(); i++) {
			mat[i][0] = x[i] == y[0] ? true : false;
			a[i][0] = mat[i][0] ? 1 : 0;
		}
		for (int i = 1; i < y.length(); i++) {
			mat[0][i] = x[0] == y[i] ? true : false;
			a[0][i] = mat[0][i] ? 1 : 0;
		}
		for (int i = 1; i < x.length(); i++) {
			for (int j = 1; j < y.length(); j++) {
				mat[i][j] = x[i] == y[j] ? true : false;
				a[i][j] = max(i, j) + (mat[i][j] ? 1 : 0);
				if (a[i][j] > p) p = a[i][j];
			}
		}
		if (a[x.length() - 1][0] > p) p = a[x.length() - 1][0];
		if (a[0][y.length() - 1] > p) p = a[0][y.length() - 1];
		cout << p << endl;
	}


	return 0;
}

C++: #include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <set>
#include <queue>
#include <string>
#include <tuple>
using namespace std;

int solve(string& X, string& Y){
  int x_size = X.size();
  int y_size = Y.size();
  
  vector<vector<int>> dp(y_size+1);
  for(int i=0;i<=y_size;i++){
    for(int j=0;j<=x_size;j++){
      dp[i].push_back(0);
    }
  }
  
  for(int i=1;i<=y_size;i++){
    for(int j=1;j<=x_size;j++){
      if(Y[i-1]==X[j-1]){
        dp[i][j] = dp[i-1][j-1]+1;
      } else {
        dp[i][j] = max(dp[i-1][j],dp[i][j-1]);
      }
    }
  }
  
  /*
  for(int i=0;i<=y_size;i++){
    for(int j=0;j<=x_size;j++){
      cout << dp[i][j] << " ";
    }
    cout << endl;
  }
  */
  
  return dp[y_size][x_size];
}

int main(void){
  int N;
  cin >> N;
  for(int i=0;i<N;i++){
    string X,Y;
    cin >> X >> Y;
    
    int lcs = solve(X,Y);
  
    cout << lcs << endl;
  }
}

C++: #include <bits/stdc++.h>
 
#define rep(i,n) for(ll i=0;i<n;++i)
#define ALL(a) (a).begin(),(a).end()
 
using namespace std;
using ll  = long long;
using pll = pair<ll, ll>;
 
const ll MOD  = 1e9+7;
const ll LINF = 1LL << 60;
const int INF = 1e9 + 7;

int solve(string x, string y){
    //dp[i][j] xの i文字目、yのj文字目までの最長共通部分列の長さ
    int dp[1010][1010] = {};

    rep(i, x.size())rep(j, y.size()){
        dp[i+1][j+1] = max(dp[i+1][j], dp[i][j+1]);
        if(x[i] == y[j])dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1);
    }

    return dp[x.size()][y.size()];
}
int main(){
    int q;
    cin >> q;

    int ans[q];

    rep(i, q){
        string x, y;
        cin >> x >> y;
        
        ans[i] = solve(x, y);
    }

    rep(i, q)cout << ans[i] << endl;
}

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

const int N = 1000;

int lcs(string a, string b) {
  int C[N+1][N+1];
  int n = a.size();
  int m = b.size();
  for (int i = 0; i <= n; i++) C[i][0] = 0;
  for (int i = 0; i <= m; i++) C[0][i] = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (a[i-1] == b[j-1]) {
        C[i][j] = C[i-1][j-1] + 1;
      } else {
        C[i][j] = C[i][j-1] > C[i-1][j] ? C[i][j-1] : C[i-1][j];
      }
    }
  }
  return C[n][m];
}

int main() {
  int q;
  cin >> 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<cstdio>
#include<string>
#include<algorithm>

using namespace std;

int N=1000;

int LCS(string x,string y){
	int c[N+1][N+1],LCSlen=0;
	int m=x.size();
	int n=y.size();
	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][j-1],c[i-1][j]);
			LCSlen=max(LCSlen,c[i][j]);
		}
	}
	return LCSlen;
}

int main(){
	string x,y;
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++){
		cin>>x;
		cin>>y;
		printf("%d\n",LCS(x,y));
	}
}