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 main(){
	buf := make([]byte, 0)
    sc.Buffer(buf, 1000000009)
	var n int 
	fmt.Scan(&n)
	dp := make([][]int, 1003)
	for i:=0; i<1003; i++ {
		dp[i] = make([]int, 1003)
	}
	input_lines := scanStringLine(2*n)
	for i:=0; i<n; i++ {
		S, T := input_lines[2*i], input_lines[2*i+1]
		lenS, lenT := len(S), len(T)
		for i:=1; i<lenS+1; i++ {
			for j:=1; j<lenT+1; j++ {
				if S[i-1] == T[j-1] {
					dp[i][j] = dp[i-1][j-1]+1
				} else if S[i-1] != T[j-1] && dp[i-1][j] > dp[i][j-1] {
					dp[i][j] = dp[i-1][j]
				} else {
					dp[i][j] = dp[i][j-1]
				}
				// 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])
	}
}

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

using namespace std;

int main(){
  string X,Y;
  int n;
  cin>>n;
  int ans[n];
  int l=0;

  for(int i=0;i<n;i++){
    ans[i]=0;
  }

  for(int m=0;m<n;m++){
  cin>>X>>Y;
 int N[X.size()+1][Y.size()+1];

  for(int i=0;i<=X.size();i++){
    for(int j=0;j<=Y.size();j++){

      N[i][j]=0;
}
  }

  /*
  for(int i=0;i<X.size();i++){
    cout<<X[i]<<endl;
  }

for(int i=0;i<Y.size();i++){
    cout<<Y[i];
  }
  */

  /* 
for(int i=0;i<=X.size();i++){
  N[i][0]=0;
  }

for(int i=0;i<=Y.size();i++){
  N[0][i]=0;
  }
  */

 int point;

  for(int i=1;i<=X.size();i++){
    for(int j=1;j<=Y.size();j++){
      if(X[i-1]==Y[j-1]){
	point=1;
	
      }else{
	point=0;
      }
       N[i][j]=max({N[i-1][j],N[i][j-1],N[i-1][j-1]+point});
       point=0;
}
   
  }
  ans[l]=N[X.size()][Y.size()];
  l++;
  // cout<<N[X.size()][Y.size()]<<endl;
  /*
  //answer
  for(int i=0;i<=X.size();i++){
    for(int j=0;j<=Y.size();j++){

      cout<<N[i][j]<<" ";
      if(j==Y.size()){
	cout<<endl;
      }
}
  }
  */

  }
  cout<<ans[0]<<endl;
 cout<<ans[1]<<endl;
 cout<<ans[2]<<endl;
}

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

int dp[1001][1001];
int main() {
  int q;
  cin >> q;
  rep(qq, q) {
    string x, y;
    cin >> x >> y;
    int len_x = x.size();
    int len_y = y.size();
    rep(i, len_x) rep(j, len_y) {
      if (x[i] == y[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]);
    }
    cout << dp[len_x][len_y] << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cstring>
#include <vector>
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define NIL -1
#define MAX 1000

static const int N = 1000;

int lcs(string X, string Y)
{
    int dp[N+1][N+1];
    int m = X.size();
    int n = Y.size();

    int maxl = 0;
    X = ' ' + X;
    Y = ' ' + Y;

    for (int i = 0; i <= m; ++i){
        dp[i][0] = 0;
    }
    for (int j = 0; j <= n; ++j){
        dp[0][j] = 0;
    }

    for (int i = 1; i <= m; ++i){
        for(int j = 1; j <=n; ++j){
            if( X[i] == Y[j] ){
                dp[i][j] = dp[i-1][j-1] + 1;
            } else {
                dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            }
            maxl = max(maxl, dp[i][j]);
        }
    }
    return maxl;
}


int main()
{
    int n;
    cin >> n;
    string X, Y;
    vector<int> v;

    rep(i, n)
    {
        cin >> X >> Y;
        v.push_back(lcs(X,Y));
    }

    rep(i, v.size()) cout << v[i] << endl;
    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], maxl = 0, i, j;
  int m = x.size();
  int n = y.size();

  x = ' ' + x;
  y = ' ' + y;
 
  for(i = 1; i <= m; i++) c[i][0] = 0;
  for(i = 1; i <= n; i++) c[0][i] = 0;

  for(i = 1; i <= m; i++){#include <iostream>

    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 x, y;
  int q, i;

  cin >> q;
  
  for(i = 0; i < q; i++){
    cin >> x >> y;
    cout << lcs(x, y) << endl;
  }
  return 0;
}

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

int main(int argc, char const *argv[]) {
  int q;
  std::cin >> q;
  for (size_t _ = 0; _ < q; _++) {
    std::string x, y;
    std::cin >> x;
    std::cin >> y;

    std::vector<std::vector<int> > dp(x.size()+1, std::vector<int>(y.size()+1));
    for (size_t ii=0; ii<x.size(); ++ii){
      for(size_t jj=0; jj<y.size(); ++jj){
        size_t i = ii + 1;
        size_t j = jj + 1;
        if (x[i]==y[j]){
          dp[i][j] = dp[i-1][j-1] + 1;
        }
        else{
          dp[i][j] = std::max(dp[i-1][j], dp[i][j-1]);
        }
      }
    }
    std::cout << dp[x.size()][y.size()] << std::endl;
  }
  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=0;i<=m;i++)c[i][0]=0;
    for(int i=1;i<=n;i++)c[0][i]=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)<<"\n";
    }
    return 0;
}