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>
using namespace std;
#define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i))
using ll = long long;
using P = pair<int, int>;
using namespace std;

template<class T> void vin(vector<T>& v, int n) {
    v.resize(n);
    for (int i = 0; i < n; ++i) {
        cin >> v[i];
    }
}

string a, b;
int dp[2000][2000];

int solve(int xi=0, int yi=0) {
    if (xi == a.size() and yi == b.size()) {
        return 0;
    }
    int& res = dp[xi][yi];
    if (~res) return res;

    if (a[xi] == b[yi]) {
        res = solve(xi+1, yi+1) + 1;
    }
    else {
        if (xi < a.size()) res = max(res, solve(xi+1, yi));
        if (yi < b.size()) res = max(res, solve(xi, yi+1));
    }
    return res;
}

int main() {
    int n;
    cin >> n;
    while (n--) {
        cin >> a >> b;
        fill(dp[0], dp[2000], -1);
        cout << solve() << endl;
    }
    return 0;
}

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

using namespace std;

int N=1000;

int LCS(string x,string y){
	int c[N+1][N+1],LCSlen=0;
	int m=x.size();
	int n=y.size();
	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][j-1],c[i-1][j]);
			LCSlen=max(LCSlen,c[i][j]);
		}
	}
	return LCSlen;
}

int main(){
	char x[1000],y[1000];
	string xst,yst;
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++){
		scanf("%s",x);
		scanf("%s",y);
		xst=x;
		yst=y;
		printf("%d\n",LCS(x,y));
	}
}

C++: #include <algorithm>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <vector>

using namespace std;

#define pb push_back

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<i_i, int> p_i;
typedef vector<int> vi;
typedef vector<vector<int> > vvi;
template<class T> using vv=vector<vector< T > >;

int main() {
  int t;
  cin >> t;
  vi results;
  for (int dataset = 0 ; dataset < t ; dataset++) {
    string a, b;
    cin >> a;
    cin >> b;
    vvi len(a.length()+1, vi(b.length(), 0));
    for (int ia = 1 ; ia <= a.length() ; ia++) {
      for (int ib = 1 ; ib <= b.length() ; ib++) {
        if (a[ia] == b[ib]) {
          len[ia][ib] = len[ia-1][ib-1]+1;
        } else {
          len[ia][ib] = max(len[ia][ib-1], len[ia-1][ib]);
        }
      }
    }
    results.pb(len[a.length()][b.length()]);
  }

  for (int it = 0 ; it < t ; it++) {
    printf("%d\n", results[it]);
  }

  return 0;
}

C++: #define _USE_MATH_DEFINES

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>
#include <list>

long long int INF = 1e18;
using namespace std;

typedef pair<long long int, long long int> P;

long long int DP[1001][1001] = {};

int main(){
	
	int n;
	cin >> n;
	
	for(int loop = 0; loop < n; loop++){
		
		string str1, str2;
		cin >> str1 >> str2;
		
		for(int i = 1; i <= str1.size(); i++){
			for(int j = 1; j <= str2.size(); j++){
				if(str1[i - 1] == str2[j - 1]){
					DP[i][j] = max(max(DP[i - 1][j - 1] + 1, DP[i - 1][j]), DP[i][j - 1]);
				}else{
					DP[i][j] = max(DP[i - 1][j], DP[i][j - 1]);
				}
			}
		}
		
		cout << DP[str1.size()][str2.size()] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;


long long L[1010][1010] {0};
int main(){
  int Q;
  cin >> Q;
  for(int i = 0; i < Q; i++){
    string X, Y;
    cin >> X >> Y;
    int xlen = X.length();
    int ylen = Y.length();
    for(int i = 1; i<= xlen; i++){
      for(int k = 1; k <= ylen; k++){
	if(X[i-1] == Y[k-1]){
	  L[i][k] = 1 + L[i-1][k-1];
	}else{
	  L[i][k] = max(L[i][k-1], L[i-1][k]);
	}
      }
    }

    cout << L[xlen][ylen] << endl;
  }

}

C++: #include <iostream>
#include <string>
using namespace	std;
int main(){

  int n;
  string s1,s2;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>s1>>s2;
    int dp[1001][1001]={};
    for(int j=1;j<=s2.size();j++){
      for(int k=1;k<=s1.size();k++){
        if(s1[k-1]==s2[j-1]) dp[j][k]=dp[j-1][k-1]+1;
        else dp[j][k]=max(dp[j-1][k],dp[j][k-1]);
      }
    }
    cout<<dp[s2.size()][s1.size()]<<endl;
  }
  return 0;

}