Go: package main

/*
最長共通部分列
*/

import (
	"bufio"
	"bytes"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func larger(l, r int) int {
	if l > r {
		return l
	}
	return r
}

var memo [1001][1001]int

func countLCS(x, y string) int {
	x = " " + x
	y = " " + y
	max := 0
	for xi := 1; xi < len(x); xi++ {
		for yi := 1; yi < len(y); yi++ {
			if x[xi] == y[yi] {
				memo[xi][yi] = memo[xi-1][yi-1] + 1
			} else {
				memo[xi][yi] = larger(memo[xi-1][yi], memo[xi][yi-1])
			}
			max = larger(max, memo[xi][yi])
		}
	}
	return max
}

func main() {
	scanner := makeScanner(1024)
	q := eGetInt(scanner)
	for i := 0; i < q; i++ {
		x := eGetLine(scanner)
		y := eGetLine(scanner)
		fmt.Println(countLCS(x, y))
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}
func min(a []int) int {
	m := a[0]
	for _, v := range a {
		if v < m {
			m = v
		}
	}
	return m
}

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

C++: /*
 * Problem Description: Longest Common Subsequence
 * Category: Dynamic Programming
 * Author: Khan
 * Date: 18th October, 2017
 */

#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 maxLength = 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]);
            maxLength = max(maxLength, c[i][j]);
        }
    }
    return maxLength;
}

int main(int argc, char const *argv[])
{
    //freopen("sample.txt", "r", stdin);
    string x, y;
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i)
    {
        cin >> x >> y;
        cout << lcs(x, y) << 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 = 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 <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <bitset>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
using namespace std;
typedef long long ll;
typedef pair<int,int> pint;
typedef vector<int> vint;
typedef vector<pint> vpint;
#define mp make_pair
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
int dx[4] = {1, 0, 0, -1};
int dy[4] = {0, 1, -1, 0};

void slove(string X, string Y){
	int dp[1000][1000];//dp[X?????????][Y?????????] = LCS
	int sizex = X.size();
	int sizey = Y.size();

	//???????????????????????????????????????????????????0????????????????????\?????????
	X = ' ' + X;
	Y = ' ' + Y;

	reps(i, 1, sizex + 1) dp[i][0] = 0;//?????????????????????0??????dp???0
	reps(i, 1, sizey + 1) dp[0][i] = 0;//?????????????????????0??????dp???0

	int ans = 0;//????°??????????
	reps(i, 1, sizex + 1){
		reps(j, 1, sizey + 1){
			if(X[i] == Y[j]) dp[i][j] = dp[i - 1][j - 1] + 1;
			else if(X[i] != Y[j]) dp[i][j] = max(dp[i][j - 1], dp[i - 1][j]);

			ans = max(ans, dp[i][j]);
		}
	}
	printf("%d\n", ans);
	return;
}

int main(void){
	int n; cin >> n;
	string s1, s2;
	rep(i, n){
		cin >> s1 >> s2;
		slove(s1, s2);
	}
	return 0;
}

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

using namespace std;
int LCS(const char* a,const char* b)
{
    int m=strlen(a); int n=strlen(b); //i???????¬????a????????????j???????¬????b?????????
    int c[m+1][n+1]; //c??°???????????¨?????°???????¬????a??????i??????????¬????b??????j????????´???LCS
    for(int i=0;i<=m;i++) c[i][0]=0;
    for(int i=0;i<=n;i++) c[0][i]=0;
    for(int i=0;i<m;i++)
        for(int j=0;j<n;j++)
        {
            if(a[i]==b[j]) c[i+1][j+1]=c[i][j]+1;
            else
            {
                c[i+1][j+1]=max(c[i][j+1],c[i+1][j]);
            }
        }
    return c[m][n];

}
int main()
{
    char *a=new char[1001];
    char *b=new char[1001];
    int q;
    while(cin>>q)
    {
        for(int i=0;i<q;i++)
        {
            cin>>a>>b;
            cout<<LCS(a,b)<<endl;
        }
    }
}

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

int Ics(string X, string Y) {
	int c[101][101];
	int m = X.length();
	int n = Y.length();
	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 if (c[i - 1][j] >= c[i][j - 1])
				c[i][j] = c[i - 1][j];
			else 
				c[i][j] = c[i][j - 1];

			maxl = max(maxl,c[i][j]);
		}
		
	}
	return maxl;
}

int main() {
	int n;
	string x, y;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x >> y;

		cout << Ics(x, y) << endl;
	}

	
}