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] = 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 <bits/stdc++.h>
using namespace std;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> P;
typedef tuple<int,int,int> tpl;

#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define SORT(c) sort((c).begin(),(c).end())
#define REVERSE(c) reverse((c).begin(),(c).end())
#define LB(a,x) lower_bound((a).begin(), (a).end(), x) - (a).begin()
#define UB(a,x) upper_bound((a).begin(), (a).end(), x) - (a).begin()

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define RFOR(i,a,b) for(int i=(a)-1;i>=(b);--i)
#define RREP(i,n) RFOR(i,n,0)

#define en "\n"

const double EPS = 1e-9;
const double PI  = acos(-1.0);
const int INT_INF = 2147483647;
const long long LL_INF = 1LL<<60;
const long long MOD = 1000000007;

#define CLR(a) memset((a), 0, sizeof(a))

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

int main(void){
    int q; cin >> q;
    REP(i,q){
        string S,T; cin >> S >> T;
        int dp[S.size()+1][T.size()+1]; CLR(dp);
        REP(i,S.size())REP(j,T.size()){
            if(S[i] == T[j]) chmax(dp[i+1][j+1], dp[i][j]+1);
            chmax(dp[i+1][j+1], dp[i][j+1]);
            chmax(dp[i+1][j+1], dp[i+1][j]);
        }
        cout << dp[S.size()][T.size()] << en;
    }
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int dp[2][1010];
int main(){
  int q;
  cin>>q;
  for(int cn=0;cn<q;cn++){
    string x,y;
    cin>>x>>y;
    memset(dp,0,sizeof(dp));
    for(int i=0;i<x.size();i++){
      int nw=i%2;
      int nt=!nw;
      for(int k=0;k<1010;k++)dp[nt][k]=0;
      for(int j=0;j<y.size();j++){
	if(j)dp[nw][j]=max(dp[nw][j],dp[nw][j-1]);
	if(x[i]==y[j])dp[nt][j+1]=max(dp[nt][j+1],dp[nw][j]+1);
	dp[nt][j]=max(dp[nt][j],dp[nw][j]);
      }
    }
    int ans=0;
    for(int i=0;i<1010;i++)ans=max(ans,dp[x.size()%2][i]);
    cout<<ans<<endl;
  }
  return 0;
}

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

class TLcsSolver
{
    int FTable[1000][1000];
    const char* FArray1;
    const char* FArray2;
    const int Fn1;
    const int Fn2;

    int Count(int i, int j)
    {
        if(i == 0 || j == 0) return 0;
        if(FArray1[i-1] == FArray2[j-1]){
            return FTable[i-1][j-1] + 1;
        }
        return std::max(FTable[i-1][j], FTable[i][j-1]);
    }
    void Solve()
    {
        for(std::size_t i = 1; i < Fn1; ++i){
            for(std::size_t j = 1; j < Fn2; ++j){
                FTable[i][j] = Count(i, j);
            }
        }
    }
public:
    TLcsSolver(const char* a, const char* b)
     : FArray1(a), FArray2(b)
     , Fn1(std::strlen(a)), Fn2(std::strlen(b))
    {
        Solve();
    }
    int Answer()const
    {
        return FTable[FArray1.size()][FArray2.size()];
    }
};

int main()
{
    int n;
    std::scanf("%d", &n);
    char a[1000];
    char b[1000];
    for(int i = 0; i < n; ++i){
        std::fgets(a, 1000, stdin);
        std::fgets(b, 1000, stdin);
        std::printf("%d", TLcsSolver(a, b).Answer());
    }
    return 0;
}

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

#define NUM 1000

string X;
string Y;
int dp[NUM + 1][NUM + 1];

void init(){
    for(int i = 0; i < NUM + 1; i++){
        for(int j = 0; j < NUM + 1; j++){
            dp[i][j] = 0;
        }
    }
}

void calc(void){
    init();

    for(int j = 1; j <= Y.size(); j++){
        for(int i = 1; i <= X.size(); i++){
            if(Y[j] == X[i]){
                dp[i][j] = dp[i - 1][j - 1] + 1;
            }else{
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
            }
        }
    }
    
    printf("%d\n", dp[X.size()][Y.size()]);

}

int main(void){
    int q;
    scanf("%d", &q);

    for(int i = 0; i < q; i++){
        cin >> X;
        cin >> Y;
        calc();
    }
}

C++: #include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
const int maxx=1010;

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

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


int main(int argc, char *argv[]){
  int n;
  cin >> n;
  for (int r = 0; r < n; r++) {

    string x, y;
    cin >> x >> y;
    string dp[y.length() + 1][x.length() + 1];

    for (int i = 0; i < y.length(); i++) {
      for (int j = 0; j < x.length(); j++) {
        if(y[i] == x[j]){
          dp[i + 1][j + 1] = dp[i][j] + y[i];
        }else{
          dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
        }
      }
    }
    int ans = 0;
    for (int i = 0; i < x.length(); i++) {
      ans = max(ans, (int)dp[y.length()][i].length());
    }
    std::cout << ans << std::endl;
  }
  return 0;
}