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<iostream>
#include<cstdio>
#include<string>
using namespace std;

#define MAX_N 1000
#define MAX_M 1000

void solve();

string s, t;
int dp[MAX_N + 1][MAX_M + 1];

void solve(){
	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];
					dp[i + 1][j + 1] = dp[i][j] + 1;
				} else {
					dp[i + 1][j + 1] = max(dp[i][j], dp[i + 1][j]);
				}
			}
		}
		cout << dp[s.size()][t.size()] << endl;
}

int main(){
	int n;
	cin >> n;
	for(int i = 0; i < n; i++){
		cin >> s >> t;
		solve();
	}
	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
using namespace std;
const int MAX=1001;
int lcs(string X,string Y) 
{
    int i=0,j=0,c[MAX][MAX],x=X.length(),y=Y.length();
    for(i=0;i<=x;i++)c[i][0]=0;
    for(i=0;i<=y;i++)c[0][i]=0;
    for(i=1;i<=x;i++) 
    for(j=1;j<=y;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[x][y];
}
int main()
{
    int n;cin>>n;
    string X,Y;
    while(n--)
    {
        cin>>X>>Y;
        cout<<lcs(X,Y)<<endl;
    }
}

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

#define MAX 1000

int lcs(string X, string Y) {
    int c[MAX+1][MAX+1];
    int m = X.size();
    int n = Y.size();
    int i, j;
    int maxlen = 0;
    X = " " + X;
    Y = " " + Y;

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

    for(i = 1 ; i <= m ; i++ ) {
        for(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][j-1], c[i-1][j]);
            }
            maxlen = max(maxlen, c[i][j]);
        }
    }
    return maxlen;
}

int main (void) {
    int N, i;
    string a, b;

    cin >> N;

    for(i = 0 ; i < N ; i++) {
        cin >> a;
        cin >> b;
        cout << lcs(a, b) << endl;
    }

    return 0;
}

C++: /*
** Longest Common Subsequence
*/

# include <cstdio>
# include <cstring>
# include <algorithm>
using namespace std;

const int MAX = 1000 + 5;

char s1[MAX], s2[MAX];
int c[MAX][MAX];

int lcs() {
    int m = strlen(s1);
    int n = strlen(s2);
    c[0][0] = 0;
    int maxl = 0;
    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 (s1[i] == s2[j]) {
                c[i][j] = c[i - 1][j - 1] + 1;
            }
            else {
                c[i][j] = max(c[i][j - 1], c[i - 1][j]);
            }
            maxl = max(maxl, c[i][j]);
        }
    }

    return maxl;
}

void solve() {
    int n;
    scanf("%d", &n);
    while (n--) {
        scanf("%s %s", s1, s2);
        printf("%d\n", lcs());
    }
}

int main() {
    // freopen("infile", "r", stdin);
    // freopen("outfile", "w", stdout);
    solve();
    return 0;
}

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

int main(void){
    int Q;
    cin >> Q;
    
    for(int q = 0;q < Q;q++){
        string x,y;
        cin >> x >> y;
        
        int dp[x.size()+1][y.size()+1];
        for(int i = 0;i < x.size()+1;i++){
            for(int j = 0;j < y.size()+1;j++){
                dp[i][j] = 0;
            }
        }
        
        for(int i = 0;i < x.size();i++){
            for(int j = 0;j < y.size();j++){
                if(x[i] == y[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[x.size()][y.size()] << endl;
    }
}

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

#define N 1000

int lcs(string x, string y) {
  int i, j, m, n, lcs[N+1][N+1];
  
  m = x.length();
  n = y.length();
  // indexずれを補正
  x = ' ' + x;
  y = ' ' + y;
  
  // 初期値
  for (i = 0; i < m + 1; i++) lcs[i][0] = 0;
  for (j = 0; j < n + 1; j++) lcs[0][j] = 0;
  // 漸化式
  for (i = 1; i <= m; i++) {
    for (j = 1; j <= n; j++) {
      if (x[i] == y[j]) lcs[i][j] = lcs[i-1][j-1] + 1;
      else lcs[i][j] = max(lcs[i-1][j], lcs[i][j-1]);
    }
  }

  return lcs[m][n];
}

int main() {
  int i, q, lcs_arr[N];
  string x, y;

  cin >> q;

  for (i = 0; i < q; i++) {
    cin >> x;
    cin >> y;
    lcs_arr[i] = lcs(x, y);
  }    

  for (i = 0; i < q; i++) cout << lcs_arr[i] << endl;
    
  return 0;
}