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

void Ics(char *X, char *Y)
{
   int c[1000][1000];
   int m, n, i, j;

   m = strlen(X);
   n = strlen(Y);

   for ( i = 1; i <= m, i++ ) {
      c[i][0] = 0;
   }
   for ( j = 0; j <= n; j++ ) {
      c[0][j] =0;
   }

   for ( i = 1; i <= m; i++ ) {
      for ( j = 1; j <=n; 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[ m ][ n ]);
}
     
int main()
{
   int q, i;
   char X[1000], Y[1000];

   scanf("%d", &q);
   for ( i = 0; i < q; i++ ) {
      scanf("%s%s", X, Y);
      Ics(X, Y);
   }
   return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
using namespace std;
void input(string &x,string &y){
	cin>>x>>y;
}
int lcs(string x,string y){
	vector<vector<int>> tb(vector<vector<int>>((int)x.size()+1,vector<int>(y.size()+1,0)));
	for(int i=1;i<(int)x.size()+1;i++){
		for(int j=1;j<(int)y.size()+1;j++){
			if(x[i]==y[j])  tb[i][j]=tb[i-1][j-1]+1;
			else tb[i][j]=max(tb[i-1][j],tb[i][j-1]);
		}
	}
	return tb[(int)x.size()][(int)y.size()];
}
int main(){
	int q;
	cin>>q;
	string x,y;
	for(int i=0;i<q;i++){
		input(x,y);
		cout<<lcs(x,y)<<endl;
	}
	return 0;
}

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



int lcs(string X,string Y){
	
	int c[720][720];
int m = X.size();
int n = Y.size();
int max1 = 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]);
		}
		max1 = max(max1,c[i][j]);
		}
	} 
	return max1;
}



int main(){
	int q;
	int a[500];
	string s1,s2;
	cin>>q;
	for(int i=0;i<q;i++){
		cin>>s1>>s2;
		a[i] = lcs(s1,s2);
	}
	for(int i=0;i<q;i++){
		cout<<a[i]<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#define lth 1000

using namespace std;

int main()
{
	int n, L[1000][1000], Lmax = 0, *save;
	string Xi[lth], Yi[lth];
	cin >> n;
	save = new int[n];
	for (int k = 0; k < n; k++)
	{
		Lmax = 0;
		string X, Y;
		cin >> X >> Y;
		for (int i = 0; i <= X.length(); i++)
		{
			if (i != 0)
				Xi[i] = X.substr(0, i );
		}
		for (int i = 0; i <= Y.length(); i++)
		{
			if (i != 0)
				Yi[i] = Y.substr(0, i );
		}
		for (int i = 0; i <= X.length(); i++)
			for (int j = 0; j <= Y.length(); j++)
			{
				if (i == 0 || j == 0)
					L[i][j] = 0;
				else if (Xi[i][i - 1] == Yi[j][j - 1])
				{
					L[i][j] = L[i - 1][j - 1] + 1;
				}
				else
				{
					L[i][j] = (L[i][j - 1] > L[i - 1][j]?L[i][j - 1] : L[i - 1][j]);
				}
				if (Lmax < L[i][j]) Lmax = L[i][j];
			}
		save[k] = Lmax;
	}
	for (int i = 0; i < n; i++)
		cout << save[i] << endl;
	//system("pause");
}

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

using namespace std;
typedef long long lint;

int dp[1111][1111];

void chmax(int& x, const int y) {
    x = max(x, y);
}

int main() {
    int Q;
    cin >> Q;
    for (int q = 0; q < Q; q++) {
        string X, Y;
        cin >> X >> Y;
        const int N = X.size(), M = Y.size();
        for (int i = 0; i <= N; i++) {
            for (int j = 0; j <= M; j++) {
                dp[i][j] = 0;
            }
        }
        for (int i = 1; i <= N; i++) {
            for (int j = 1; j <= M; j++) {
                chmax(dp[i][j], dp[i-1][j]);
                chmax(dp[i][j], dp[i][j-1]);
                if (X[i-1] == Y[j-1]) chmax(dp[i][j], dp[i-1][j-1] + 1);
            }
        }
        cout << dp[N][M] << 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;//??¨X[0]????????\?????????
	Y=' '+Y;//??¨Y[0]????????\?????????
	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;
		int ans=lcs(s1,s2);
		if(ans<=20)cout<<ans<<endl;
		else cout<<"20"<<endl;
	}
	return 0;
}

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

using namespace std;

short dp[1010][1010];

int main(void)
{
    int q;
    cin >> q;
    while (q)
    {
        string X, Y;
        cin >> X >> Y;
        int Xs = X.size(), Ys = Y.size();
        for (int i = 0; i < Xs; i++) dp[i][0] = 0;
        for (int j = 0; j < Ys; j++) dp[0][j] = 0;
        for (int i = 0; i < Xs; i++)
        {
            for (int j = 0; j < Ys; j++)
                dp[i + 1][j + 1] = ((X[i] == Y[j]) ? dp[i][j] + 1 : max(dp[i + 1][j], dp[i][j + 1]));
        }
        cout << dp[Xs][Ys] << endl;
        q--;
    }
    return 0;
}