Go: package main

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

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func bordersInt(in_map [][]int, invalid int) [][]int{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]int, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]int, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func bordersString(in_map [][]string, invalid string) [][]string{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]string, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]string, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func maxInt(args... int) int{
	sort.Ints(args)
	return args[len(args)-1]
}

func f() {
	var S, T string
	fmt.Scan(&S)
	fmt.Scan(&T)
	lenS, lenT := len(S), len(T)
	dp := make([][]int, lenS+1)
	for i:=0; i<lenS+1; i++ {
		dp[i] = make([]int, lenT+1)
	}
	for i:=1; i<lenS+1; i++ {
		for j:=1; j<lenT+1; j++ {
			if S[i-1] == T[j-1] {
				dp[i][j] = maxInt(dp[i-1][j-1]+1, dp[i-1][j], dp[i][j-1])
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
		}
	}
	fmt.Println(dp[lenS][lenT])
}

func main(){
	var n int 
	fmt.Scan(&n)
	for i:=0; i<n; i++ {
		f()
	}
}

C++: #include<iostream>
#include<string>
#include<cstring>
#include<algorithm>
#define MAX_N 1001

int solve(std::string s,std::string t){
        int dp[MAX_N][MAX_N]={0};
        int n,m;
        n=s.size();
       m=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]=std::max(dp[i][j+1],dp[i+1][j]);
                }
        }
        return dp[n][m];
}

int main(){
        int q;
        std::cin>>q;
        for(int i=0;i<q;i++){
                std::string s,t;
                std::cin >> s>>t;
                std::cout<<solve(s,t)<<std::endl;
        }
        return 0;
}

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

int main() {
  int q; cin >> q;
  string A, B;
  for (int i=0; i<q; i++) {
    cin >> A >> B;
    vector<vector<int>> LCS(A.length()+1, vector<int>(B.length()+1,0));
    for (int j=1; j<=A.length(); j++) {
      for (int k=1; k<=B.length(); k++) {
        if(A[j]==B[k]) LCS[j][k]=LCS[j-1][k-1]+1;
        else LCS[j][k]=max(LCS[j-1][k],LCS[j][k-1]);
      }
    }
    cout << max({LCS[A.length()][B.length()],LCS[A.length()-1][B.length()],LCS[A.length()][B.length()-1]}) << "\n";
  }
}

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

string u, v;
vector<vector<int> > memoization;

int lenLCS(int i, int j) {
  int current_max = INT_MIN;
  int attempt;
  if (i == -1)
    return 0;
  if (j == -1)
    return 0;
  if (memoization[i][j] != -1)
    return memoization[i][j];
  if (u[i] == v[j]) {
    attempt = 1 + lenLCS(i-1,j-1);
    if (attempt > current_max)
      current_max = attempt;
  }
  attempt = lenLCS(i-1,j);
  if (attempt > current_max)
    current_max = attempt;
  attempt = lenLCS(i,j-1);
  if (attempt > current_max)
    current_max = attempt;
  memoization[i][j] = current_max;
  return memoization[i][j];
}

int main(int argc, char **argv) {
  ios_base::sync_with_stdio(false);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> u >> v;
    memoization = vector<vector<int> > (u.size(), vector<int> (v.size(), -1));
    cout << lenLCS(u.size()-1, v.size()-1) << endl;
  }
  return 0;
}

C++: #include <stdio.h>
#include <string.h>

#define M 1001

int n;

char x[M],y[M];
 
void lcs(void){
  int i,j;
  int len_x, len_y,graph[M][M];

  len_x=strlen(x);
  len_y=strlen(y);
  for(i=1;i<M;i++){
    for(j=1;j<M;j++){
      graph[i][j]=0;
    }
  }
  for(i=1;i<=len_x;i++){
    for(j=1;j<=len_y;j++){
      if(x[i-1]==y[j-1]) graph[i][j]=graph[i-1][j-1]+1;

      else{
        if(graph[i-1][j]>=graph[i][j-1]) graph[i][j]=graph[i-1][j];
        else graph[i][j]=graph[i][j-1];
      }
    }
  }
  printf("%d\n",graph[len_x][len_y]);
}
     
int main()
{
  int i;
   
  scanf("%d",&n);
 
  for(i=0;i<n;i++){
    scanf("%s",x);
    scanf("%s",y);
    lcs();
  }
  return 0;
}

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;
}