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<algorithm>
#include<string.h>
using namespace std;

int n, m;
char s[1000], t[1000];
int dp[1001][10001];

int main(void){
    cin >> n;

    for(int i=0;i<n;i++){
        cin >> s;
        cin >> t;
        int sizeofs = strlen(s);
        int sizeoft = strlen(t);
        for(int i=0;i<sizeofs;i++){
            for(int j=0;j<sizeoft;j++){
                if(s[i] == t[j]){
                    dp[i+1][j+1] = dp[i][j] + 1;
                }else{
                    dp[i+1][j+1] = max(dp[i][j+1],dp[i+1][j]);
                }
                cout << s[3] << endl;
            }
        }
        cout << dp[sizeofs][sizeoft] <<endl;
    }

    return 0;
}

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

#define NMAX 1000
int lcs[NMAX+1][NMAX+1];

int solveLCS(string S1, string S2) {
	int n1 = S1.size(), n2 = S2.size(), vmax = 0;
	
	for (int i = 0; i <= n1; i++) lcs[i][0] = 0;
	for (int i = 0; i <= n2; i++) lcs[0][i] = 0;

	for (int i = 1; i <= n1; i++) {
		for (int j = 1; j <= n2; j++) {
			if (S1[i - 1] == S2[j - 1]) {
				lcs[i][j] = lcs[i - 1][j - 1] + 1;
			}
			else {
				lcs[i][j] = max(lcs[i - 1][j], lcs[i][j - 1]);
			}
			vmax = max(vmax, lcs[i][j]);
		}
	}
	return vmax;
}

int main() {
	int N; cin >> N;
	string S1, S2;

	for (int i = 0; i < N; i++) {
		cin >> S1 >> S2;
		cout << solveLCS(S1, S2) << endl;
	}
	return 0;
}

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

using namespace std;

string s, t;

int main() {
	int n;
	cin >> n;
	while (n--) {
		//dp[i][j] := s???i??????????????§???t???j??????????????§?????£?????¨??????LCS
		vector<vector<int>> dp(200, vector<int>(200));
		cin >> s >> t;
		dp[0][0] = (s[0] == t[0]);
		for (int i = 1; i < s.size(); i++)dp[i][0] = (bool)(dp[0][0] + (s[i] == t[0]));
		for (int j = 1; j < t.size(); j++)dp[0][j] = (bool)(dp[0][0] + (s[0] == t[j]));
		
		for (int i = 1; i < s.size(); i++) {
			for (int j = 1; j < t.size(); j++) {
				if (s[i] == t[j])dp[i][j] = dp[i-1][j-1]+1;
				else dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
			}
		}
		cout << dp[s.size() - 1][t.size() - 1] << endl;
	}
}

C++: #include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <set>
#include <queue>
#include <map>
#include <stdlib>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<ld> vld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define INF ((int)1e9)
#define INFLL ((ll)1e18)
#define MOD (1000000007LL)


int main(int argc, const char * argv[]) {
    int Q;
    string X, Y;
    cin >> Q;
    for (int q = 0; q < Q; ++q) {
        cin >> X >> Y;
        int DP[1001][1001];
        memset(DP, 0, sizeof(DP));
        for (int sx = 1; sx <= X.size(); ++sx) {
            for (int sy = 1; sy <= Y.size(); ++sy) {
                DP[sx][sy] = max(DP[sx][sy-1], DP[sx][sy-1]);
                if (X[sx] == Y[sy]) {
                    DP[sx][sy] = max(DP[sx][sy], DP[sx-1][sy-1]+1);
                }
            }
        }
        cout << DP[X.size()][Y.size()] << endl;
    }
    return 0;
}

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

int C[1001][1001];

int lcs(string X,string Y){
  int m=X.length();
  int n=Y.length();
  int maxl=0;
  X=' '+X;
  Y=' '+Y;
  for (int i=0;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.at(i)==Y.at(j)){
        C[i][j]=C[i-1][j-1]+1;//同じのがでてきたら足す
      }else{
        C[i][j]=max(C[i-1][j],C[i][j-1]);//同じでない場合　上と左の多い方
      }
      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++: //#if 0
//????????????????§£?????????????????????????????????????????????????????????C++??§string??????????????§???
//?????????????????§???????????§???AOJ?????????????????????Runtime Error??????????????????????????????
//??£????????¨??????????????????????????????????????????????????????Runtime Error???????????¨???????????????
//??§???????????????????????????????????§???
//#endif
#include<iostream>
#include<string>
#define lth 1000

using namespace std;

int main()
{
	int n, L[1010][1010], Lmax = 0, *save;
	string *Xi, *Yi;
	cin >> n;
	save = new int[n];
	if (n <= 20)
	{
		Xi = new string[lth];
		Yi = new string[lth];
	}
	else
	{
		Xi = new string[100];
		Yi = new string[100];
	}
	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;
}