Go: package main

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

const max int = 1000 + 1
var A [][]int

func lcs(x, y string) int {
	x = " " + x
	y = " " + y
	for i:=0;i<len(x); i++ {
		for j:=0;j<len(y); j++ {
			A[i][j] = 0
		}
	}
	for i:=1; i<len(x); i++ {
		for j:=1; j<len(y); j++ {
			if x[i] == y[j] {
				A[i][j] = A[i-1][j-1] + 1
			} else if A[i-1][j] > A[i][j-1] {
				A[i][j] = A[i-1][j]
			} else {
				A[i][j] = A[i][j-1]
			}
		}
	}
	return A[len(x)-1][len(y)-1]
}

func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num 
}

func nextStr(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}


func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	A = make([][]int, max)
	for i := range A {
		A[i] = make([]int, max)
	}
	n := nextInt(scanner)
	for i:=0; i<n; i++ {
		x := nextStr(scanner)
		y := nextStr(scanner)
		fmt.Printf("%d\n", lcs(x, y))
	}
}

C++: #include<stdio.h>
#include<string.h>
  
#define MAX 1000
  
int main(){
  int i,j,m,q,x,y,c[MAX+1][MAX+1];
  char X[MAX],Y[MAX];
  
  scanf("%d",&q);
  
  for(i=0;i<strlen(X);i++)
    c[i][0] = 0;
  for(j=0;j<strlen(Y);j++)
    c[0][j] = 0;
  
  for(m=0;m<q;m++){
    scanf("%s",X);
    scanf("%s",Y);
    x = strlen(X);
    y = strlen(Y);
    for(i=0;i<x;i++)
      c[i][0] = 0;
    for(j=0;j<y;j++)
      c[0][j] = 0;
  
    for(i=1;i<=x;i++){
      for(j=1;j<=y;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];
      }
    }
    printf("%d\n",c[x][y]);
  }
  
  return 0;
}

C++: //Longest Common Subsequence
#include <iostream>
#include <string>

using namespace std;

static const int N = 1000;

int lcs(string X, string Y) {
    int c[N + 1][N + 1] = {};
    int maxl = 0, m = int(X.size()), n = int(Y.size());
    X = X;
    Y = Y;
    for(int i = 0; i < m + 1; i++) c[i][m] = 0;
    for(int j = 0; j < n + 1; j++) c[n][j] = 0;
    for(int i = m - 1; i >= 0; i--) {
        for(int j = n - 1; j >= 0; j--) {
            if(X[i] == Y[j]) c[i][j] = 1 + c[i + 1][j + 1];
            else c[i][j] = max(c[i][j + 1], c[i + 1][j]);
        }
    }
    return c[0][0];

}

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++: #define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
using namespace std;
#define len(n) (int)n.length()
#define pb push_back
#define ll long long
#define make_pair mkp
#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define ALL(v) (v).begin(), (v).end()
#ifdef DBGPRT
#define dbg(n) cerr << "//" << #n << ":" << n <<endl
#else
#define dbg(n) ;
#endif
typedef pair<ll, ll> LLARR;
#define INF 999999999
const double PI = 3.1415926535897932384626433832795;

ll lcs(string s1, string s2)
{
	int m = len(s1);
	int n = len(s2);
	s1 = ' '+s1;
	s2 = ' '+s2;
	int (*mat)[1001];
	mat = new int[1001][1001];
	REP(i, m)
	{
		mat[i][0] = 0;
	}
	REP(i, n)
	{
		mat[0][i] = 0;
	}
	int maxx = 0;
	FOR(i, 1, m+1)
	{
		FOR(j, 1, n+1)
		{
			if (s1[i] == s2[j])
				mat[i][j] = mat[i-1][j-1] + 1;
			else
				mat[i][j] = max(mat[i][j-1], mat[i-1][j]);
			maxx = max(maxx, mat[i][j]);
		}
	}
	delete[] mat;
	return maxx;
}
int main()
{
	ios::sync_with_stdio(false);

	int n;
	cin >> n;
	REP(i, n)
	{
		string s1;
		cin >> s1;
		string s2;
		cin >> s2;
		cout << lcs(s1, s2);
	}
	cout << endl;
	return 0;
}

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

#define MAX_N 1000
#define MAX_M 1000

void solve();

string s, t;
int dp[MAX_N + 1][MAX_M + 1];

void solve(){
	for(int i = 0; i < s.size(); i++){
		for(int j = 0; j < t.size(); j++){
			if(s[i] == t[j]){
				dp[i + 1][j + 1];
					dp[i + 1][j + 1] = dp[i][j] + 1;
				} else {
					dp[i + 1][j + 1] = max(dp[i][j], dp[i + 1][j]);
				}
			}
		}
		cout << dp[s.size()][t.size()] << endl;
}

int main(){
	int n;
	cin >> n;
	for(int i = 0; i < n; i++){
		cin >> s >> t;
		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++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;

template<class T>
void chmax(T &a, T b) {if (a < b) a = b;}
template<class T>
void chmax(T &a, initializer_list<T> list) {chmax(a, *max_element(list.begin(), list.end()));}
ll dp[1010][1010];
int main(int argc, char **argv)
{
	ll n; cin >> n;
	for (ll i = 0; i < n; ++i)
	{
		string a, b; cin >> a >> b;
		memset(dp, 0, sizeof dp);
		for (ll i = 0; i < a.size(); ++i)
		{
			for (ll j = 0; j < b.size(); ++j)
			{
				
				if (a[i] == b[j])
					chmax(dp[i+1][j+1], dp[i][j]+1);
				chmax(dp[i+1][j+1], {dp[i+1][j], dp[i][j+1]});
			}
		}
		std::cout << dp[a.size()][b.size()] << std::endl;
	}
}

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

int main(){
  int q;
  cin >> q;
  for(int m=0; m<q; m++){
    string wordx, wordy;
    cin >> wordx >> wordy;
    int L[1000][1000]={0};
    
    for(int j=0; j<wordy.size(); j++){
      for(int i=0; i<wordx.size(); i++){
	if(wordx[i]==wordy[j]){
	  L[i+1][j+1] = 1+L[i][j];
	}
	else{
	  L[i+1][j+1] = max(L[i+1][j], L[i][j+1]);
	}
      }
    }
    cout << L[wordx.size()-1][wordy.size()-1] << endl;
    
    
  }
}

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

int c[1001][1001];

int lcs(string X,string Y){
	

int m = X.size();
int n = Y.size();
int max1 = 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]);
		}
		max1 = max(max1,c[i][j]);
		}
	} 
	return max1;
}



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

C++: #include <bits/stdc++.h>
using namespace std;

#if __has_include("print.hpp")
  #include "print.hpp"
#endif

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

typedef long long ll;
typedef pair<int, int> p;

vector<vector<int>> dp(2000, vector<int>(2000));

void solve(string s, string t){
  int n = int(s.size());
  int m = int(t.size());

  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if(s[i] == t[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[n][m] << endl;
}

int main(){
  int n;
  cin >> n;
  for (int i = 0; i < n; i++)
  {
    string s, t;
    cin >> s >> t;
    solve(s, t);
  }
}