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 <bits/stdc++.h>
#include<algorithm>
#define int long long
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define INF 1000000000000
int MOD=1000000007;
int n;
int dp[1001][1001];
signed main() {
cin>>n;
rep(ii,n){
  rep(p,1001){
    rep(q,1001){
      dp[p][q]=0;
    }
  }
  string x,y;
  cin>>x>>y;
  rep(i,x.size()){
    rep(j,y.size()){
      if(x[i]==y[j]){dp[i+1][j+1]=1+dp[i][j];}
      else dp[i+1][j+1]=max(dp[i][j+1],dp[i+1][j]);
    }
  }
cout<<dp[x.size()][y.size()]<<endl;
 }
}

C++: #include <bits/stdc++.h>
#define int long long
typedef long long ll;
using namespace std;

ll N;

void lcs(string a, string b){
    int DP[a.size()+1][b.size()+1]={{0}};
    for(int i=0;i<=a.size();i++) DP[i][0]=0;
    for(int i=0;i<=b.size();i++) DP[0][i]=0;
    for(int i=1;i<=a.size();i++){
        for(int j=1;j<=b.size();j++){
            if(a[i-1]==b[j-1]) DP[i][j] = DP[i-1][j-1] + 1;
            else DP[i][j] = max(DP[i][j-1], DP[i-1][j]);
            //cout << " " << DP[i][j];
        }
        //cout << endl;
    }
    cout << DP[a.size()][b.size()] << endl;
    return;
}

signed main(){
    cin >> N;
    for(int i=0;i<N;i++){
        string A, B;
        cin >> A >> B;
        lcs(A, B);
    }
    return 0;
}

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

#define REP(i, n) for(int i = 0; i < (n); i++)

string str1, str2;
int dp[1001][1001];
int k;

int solve(int i, int j)
{
  if(dp[i][j] > 0)
    return dp[i][j];
  if(i == str1.size() || j == str2.size()){
    if(i != str1.size()){
      return solve(i + 1, k);
    }else{
      return 1;
    }
  }
  if(str1[i] == str2[j]){
    k = j + 1;
    dp[i][j] = solve(i + 1, j + 1);
    return dp[i][j] + 1;
  }else{
    return solve(i, j + 1);
  }
}

int main()
{
  int q, n, ans = 0;
  cin >> q;
  cin.ignore();
  fill(&dp[0][0], &dp[1001][0], -1);
  REP(i, q){
    getline(cin, str1);
    getline(cin, str2);
    if(str1.size() < str2.size())
      swap(str1, str2);
    REP(i, str1.size()){
      n = solve(i, 0) - 1;
      ans = (n > ans) ? n : ans;
    }
  }
  cout << ans << endl;
}

C++: #include <iostream>
#include <array>
#include <algorithm>
#include <vector>
#include <bitset>
#include <set>
#include <unordered_set>
#include <cmath>
#include <complex>
#include <deque>
#include <iterator>
#include <numeric>
#include <map>
#include <unordered_map>
#include <queue>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <limits>
#include <iomanip>
#include <functional>
#include <cassert>
using namespace std;

using ll=long long;
template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
using vll = V<ll>;
using vvll = V<vll>;
#define rep(i, k, n) for (ll i=k; i<(ll)n; ++i)
#define REP(i, n) rep(i, 0, n)
#define ALL(v) v.begin(),v.end()
template < class T > inline bool chmax(T& a, T b) {if (a < b) { a=b; return true; } return false; }
template < class T > inline bool chmin(T& a, T b) {if (a > b) { a=b; return true; } return false; }
#define DEBUG_VLL(vec) REP(sz, vec.size()) std::cerr<<vec[sz]<<(sz==vec.size()-1?'\n':' ');

const long long MOD = 1000000007;
const long long HIGHINF = (long long)1e18;
const int INF = (int)1e9;

int q;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> q;
    while (q-->0) {
        string x, y; cin >> x >> y;
        vvll dp(x.size() + 1, vll(y.size() + 1, 0));
        for (int xi = 0; xi < x.size(); xi++) {
            for (int yi = 0; yi < y.size(); yi++) {
                if (x[xi] == y[yi]) dp[xi + 1][yi + 1] = dp[xi][yi] + 1;
                else dp[xi + 1][yi + 1] = max(dp[xi][yi + 1], dp[xi + 1][yi]);
            }
        }
        cout << dp[x.size()][y.size()] << '\n';
    }
    return 0;
}