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++: #define _CRT_SECURE_NO_WARNINGS

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

class LCS{
private:	
	char x[1000 + 1];
	char y[1000 + 1];
	int lcs[1000][1000];
public:
	LCS(const char x[], const char y[]);
	int calcLCS();
	int calcLCS(int i, int j);
};

LCS::LCS(const char x[], const char y[])
{
	strcpy(this->x, x);
	strcpy(this->y, y);
	for (int i = 0; (this->x)[i] != '\0'; i++) {
		for (int j = 0; (this->y)[j] != '\0'; j++) {
			lcs[i][j] = -1;
		}
	}
}

int LCS::calcLCS(){
	int i, j;
	for (i = 0; ; i++) {
		if (x[i + 1] == '\0') break;
	}
	for (j = 0; ; j++) {
		if (y[j + 1] == '\0') break;
	}
	return calcLCS(i, j);
}

int LCS::calcLCS(int i, int j)
{
	if (i < 0 || j < 0) return 0;

	if (lcs[i][j] != -1) return lcs[i][j];

	if (x[i] == y[j]) lcs[i][j] = calcLCS(i - 1, j - 1) + 1;
	else lcs[i][j] = max(calcLCS(i, j - 1), calcLCS(i - 1, j));
	return lcs[i][j];
}

int main(void)
{
	int q;
	cin >> q;
	cin.ignore(1);
	for (int i = 0; i < q; i++) {
		char x[1000 + 1] = "\0";
		char y[1000 + 1] = "\0";
		cin.getline(x, 1000 + 1);
		cin.getline(y, 1000 + 1);
		LCS *lcs = new LCS(x, y);
		cout << lcs->calcLCS() << endl;
		delete lcs;
	}

	return 0;
}

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

int n, m;
char s[1000], t[1000];
int dp[1001][10001];

int main(void){
    cin >> n;
    for(int i=0;i<n;i++){
        cin >> s;
        cin >> t;
        int sizeofs = strlen(s);
        int sizeoft = strlen(t);
        for(int i=0;i<sizeofs;i++){
            for(int j=0;j<sizeoft;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[sizeofs][sizeoft] <<endl;
    }

    return 0;
}

C++: //	created : 16/03/15
// 	author   : Rp7rf
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <set>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
#define rep(i,a) for(int i = 0 ; i < a ; i ++)
#define loop(i,a,b) for(int i = a ; i < b ; i ++)
#define vi vector<int>
#define mp make_pair
#define pb push_back
#define MOD 1000000007
#define INF 1e9
 
int main(void){
    int q;
    string a,b;
    int dp[1010][1010];
    cin>>q;

    while(q--){
        cin>>a>>b;
        for(int j = 0 ; j < a.size() ; j ++){
            for(int i = 0 ; i < b.size() ; i ++){
                if(a[j] == b[i]){
                    dp[j+1][i+1] = dp[j][i]+ 1;
                }else{
                    dp[j+1][i+1] = max(dp[j][i+1],dp[j+1][i]);
                }
            }
        }
        cout<<dp[a.size()][b.size()]<<endl;
    }
}

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

 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<stdio.h>
#include<string.h>
   
int LCS(char *X, char *Y){
  int i,j,m,n,c[1001][1001];
  m = strlen(X);
  n = strlen(Y);
     
  for(i=0; i<m; i++){
    c[i][0] = 0;
  }
  for(j=0; j<n; j++){
    c[0][j] = 0;
  }
   
  for(i=1;i<m+1;i++){
    for(j=1;j<n+1;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];
    }
  }
  return c[i-1][j-1];
}
   
int main(){
  int i, q;
  char X[1001], Y[1001];
     
  scanf("%d", &q);
  for(i=0; i<q; i++){
    scanf("%s", X);
    scanf("%s", Y);
    printf("%d\n", LCS(X, Y));
   
  }
  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#define _A_ true
using namespace std;

int main(){
  int n,AC=0;
  int dp[1010][1010];
  char A[1500],B[1500];
  scanf("%d",&n);
  while(_A_){
    if(AC == n)break;
    scanf("%s",A);
    scanf("%s",B);
    for(int i=0;i<1010;i++)for(int j=0;j<1010;j++)dp[i][j]=0;

    for(int i=0;i<strlen(A);i++){
      for(int j=0;j<strlen(B);j++){
	if(A[i] == B[j]){
	  dp[i+1][j+1]=dp[i][j]+1;
	}
	else{
	  if(dp[i+1][j] > dp[i][j+1]){
	    dp[i+1][j+1]=dp[i+1][j];
	  }
	  else {
	    dp[i+1][j+1] = dp[i][j+1];
	  }
	}
      }
    }
    printf("%d\n",dp[strlen(A)][strlen(B)]);
    AC++;
  }
  return 0;
}

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;
 int point;

  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=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()];

  cout<<N[X.size()][Y.size()]<<endl;
  // l++;

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

 return 0;
}