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 <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cstring>
#include <queue>
#include <vector>
#include <functional>
#include <map>
#include <set>
#include <cmath>
#include <string>
#define SIZE 200005
#define INF 1000000005LL

#include<iostream>

using namespace std;
typedef long long int ll;
typedef pair <int,int> P;

static const int N = 1005;

int n;
ll K;
int dp[N][N];

int main()
{
	scanf("%d",&n);
	string s1,s2;
	for(int k=0;k<n;k++){
		//scanf("%s",&s1);
		//scanf("%s",&s2);
		cin >> s1 >> s2;
		s1 = ' ' + s1;
		s2 = ' ' + s2;
		for(int i=0;i<s1.size();i++)dp[i][0]=0;
		for(int i=0;i<s2.size();i++)dp[0][i]=0;
		for(int i=1;i<s1.size();i++){
			for(int j=1;j<s2.size();j++){
				if(s1[i]==s2[j]){
					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[i][j]);
			}
		}
		printf("%d\n",dp[s1.size()-1][s2.size()-1]);
	}

	return 0;
}

C++: #include <iostream>
#include <algorithm>
using namespace std;
int LCS(char *x,char *y);
char x[1000], y[1000];
int lcs[1000][1000];
int main()
{
	int q,i,j;

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

int LCS(char *x, char *y)
{
	int i, j;
	int len_x, len_y;
	len_x = strlen(x);
	len_y = strlen(y);
	
	for (i = 0; i < len_x; i++) {
		if (x[0] == y[i]) {
			lcs[0][i] = 1;
		}
		else {
			lcs[0][i] = 0;
		}
	}
	for (i = 0; i < len_x; i++) {
		if (x[i] == y[0]) {
			lcs[i][0] = 1;
		}
		else {
			lcs[i][0] = 0;
		}
	}

	for (i = 0; i < len_x; i++) {
		for (j = 0; j < len_y; j++) {
			if (x[i] == y[j]) {
				lcs[i][j] = lcs[i - 1][j - 1] + 1;
				//printf("lcs[%d][%d]=%d\n", i, j, lcs[i - 1][j - 1] + 1);
			}
			if (x[i] != y[j]) {
				lcs[i][j] = max(lcs[i - 1][j], lcs[i][j - 1]);
				//printf("lcs[%d][%d]=%d\n", i, j, max(lcs[i - 1][j], lcs[i][j - 1]));
			}
		}
	}
	//cout << endl;

	for (i = 0; i < len_x; i++) {
		for (j = 0; j < len_y; j++) {
			//printf("%d ", lcs[i][j]);
		}
		//cout << endl;
	}
	//cout << "len_x=" << len_x << endl << "len_y=" << len_y << endl;
			
	return lcs[len_x-1][len_y-1];
}

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

int dp[1005][1005];

int main(){
    int q;
    cin>>q;
    while(q--){
        string s,t;
        cin>>s>>t;
        for(int i=0; i<1005; ++i){
            for(int j=0; j<1005; ++j){
                dp[i][j]=0;
            }
        }
        for(int i=0; i<s.size(); ++i){
            for(int j=0; j<t.size(); ++j){
                if(s[i]==t[j]){
                    dp[i+1][j+1]=max(dp[i+1][j+1],dp[i][j]+1);
                }
                dp[i+1][j+1]=max(dp[i+1][j+1],dp[i][j+1]);
                dp[i+1][j+1]=max(dp[i+1][j+1],dp[i+1][j]);
            }
        }
        cout<<dp[s.size()][t.size()]<<endl;
    }
}

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

static const int N = 1000;

int lcs(string X,string Y){
    int c[N+1][N+1];    //c[i][k]???Xi??¨Yk???LCS??¨??????????????????
    int m = X.size();
    int n = Y.size();
    int maxl = 0;
    X = ' ' + X; // X[0]?????????????????\
    Y = ' ' + Y;
    for(int i=1;i<=m;i++) c[i][0] = 0;
    for(int k=1;k<=n;k++) c[0][k] = 0;

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

    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<vector>
//#include<algorithm>

const static int MAX = 1001;
std::string X, Y;
int LCS[MAX][MAX];

int main(void){
    int q, x_size, y_size;
    std::cin >> q;
    for(int i = 0; i < q; i++){
	std::cin >> X >> Y;
	LCS[0][0] = 0;
	LCS[0][1] = 0;
	LCS[1][0] = 0;
	x_size = X.size();
	y_size = Y.size();
	for(int j = 0; j < X.size(); j++){
	    for(int k = 0; k < Y.size(); k++){
		if(X[j] == Y[k]){
		    LCS[j+1][k+1] = LCS[j][k] + 1;
		}else if(X[j] != Y[k]){
		    LCS[j+1][k+1] = std::max(LCS[j][k+1], LCS[j+1][k]);
		}
	    }
	}
	std::cout << LCS[x_size][y_size] << std::endl;
    }

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vl vector<ll>
#define pl pair<ll,ll>
#define rep(i,b) for(ll i=0;i<b;i++)
#define all(v) (v).begin(),(v).end()

ll lcs(string X,string Y){
    ll c[1001][1001];
    ll m=X.size();
    ll n=Y.size();
    ll maxl=0;
    X=' '+X;
    Y=' '+Y;
    for (int i = 0; i <=m ; ++i)c[i][0]=0;
    for (int j = 0; 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;
ll n;cin>>n;
rep(i,n){
    cin>>s1>>s2;
    cout<<lcs(s1,s2)<<endl;
}
}