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<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>
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=0;i<=m;i++) c[i][0]=0;
    for(int j=0;j<=m;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<algorithm>
#include<vector>
#include<stack>
#include<queue>
#include<list>
#include<string>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<cmath>
using namespace std;

const int NIL = -1;
const int MAX = 2000001;
int c[1001][1001];

int main(void)
{
	int q, m, n;
	string a, b;
	cin >> q;
	for (int i = 0; i < q; i++) {
		cin >> a >> b;
		m = a.length();
		n = b.length();
		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 (a[i - 1] == b[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];
			}
		}
		cout << c[m][n] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#ifdef ENABLE_DEBUG_OUTPUT
#define DEBUG_LOG(s) cout << s << endl;
#else
#define DEBUG_LOG(s) void();
#endif

int lcs(string a, string b) {
    vector<vector<int>> dp(a.size(), vector<int>(b.size(), 0));
    //init
    dp[0][0] = (a[0] == b[0]);
    for (auto i = 1; i < (int)a.size(); i++) dp[i][0] = dp[i - 1][0] or (a[i] == b[0]);
    for (auto i = 1; i < (int)b.size(); i++) dp[0][i] = dp[0][i - 1] or (a[0] == b[i]);
    // dp
    for (auto i = 1; i < (int)a.size(); i++) {
        for (auto j = 1; j < (int)b.size(); j++) {
            if(a[i] == b[j]) dp[i][j] = dp[i - 1][j - 1] + 1;
            else dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
        }
    }

//    for (auto i = 0; i < (int)b.size(); i++) {
//        for (auto j = 0; j < (int)a.size(); j++) {
//            cout << dp[j][i] << " ";
//        }
//        cout << endl;
//    }
    return dp[a.size() - 1][b.size() - 1];
}

int main(){
    int q;
    cin >> q;

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

    return 0;
}

C++: #include<stdio.h>
#include<string>
#include<iostream>
using namespace std;
int main(){
  int n,dp[1010][1010],i,j,k,a,b;
  scanf("%d\n",&n);
  for(k=0;k<n;k++){
    string x,y;
    cin >> x >> y;
    a=x.size(),b=y.size();
    for(i=0;i<=a;i++){
      for(j=0;j<=b;j++){
        dp[i][j]=0;
      }
    }
    for(i=1;i<=a;i++){
      for(j=1;j<=b;j++){
        if(x[i-1]==y[j-1]){
          dp[i][j]=dp[i-1][j-1]+1;
        }
        else{
          if(dp[i-1][j]>dp[i][j-1]){
            dp[i][j]=dp[i-1][j];
          }
          else{
            dp[i][j]=dp[i][j-1];
          }
        }
      }
    }
      printf("%d\n",dp[a][b]);
    }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define REP(i,n) for(int i=1;i<=n;i++)
typedef long long ll;

int dp[1005][1005];
int main(){
	int q;
	cin >> q;
	rep(i,q) {
		string s, t;
		cin >> s >> t;
		int N = s.size();
		int M = t.size();
		rep(i, N) {
			rep(j, M) {
				if (s[i] == t[j]) {
					dp[i + 1][j + 1] = dp[i][j] + 1;
				} else {
					dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
				}
			}
		}
		cout << dp[N][M] << endl;
	}
	
    return 0;
}

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

using namespace std;

int solve(string s1, string s2){
    int L[s1.size()+1][s2.size()+1];
    for(int i=0;i<=s1.size();i++){
        for(int j=0;j<=s2.size();j++){
            if(i==0 || j==0){
                L[i][j]=0;
            }
            else if(s1[i] == s2[j]){
                L[i][j] = 1 + L[i-1][j-1];
            }
            else{
                L[i][j] = max(L[i][j-1],L[i-1][j]);
            }
        }
    }
    return L[s1.size()][s2.size()];
}

int main(){
    int n ; cin >> n;
    for(int i=0;i<n;i++){
        string s1,s2; cin>> s1 >> s2;\
        cout << solve(s1,s2) << endl;
    }
}