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

int q;
string X, Y;


int main(void) {
  cin >> q;
  for (int i = 0; i < q; i++) {
    int dp[1000][1000];
    cin >> X >> Y;
    memset(dp, 0, sizeof(dp));

    dp[0][0] = X[0] == Y[0];
    for (int j = 1; j < Y.size(); j++) dp[0][j] = dp[0][j-1] || X[0] == Y[j];
    for (int j = 1; j < X.size(); j++) dp[j][0] = dp[j-1][0] || X[j] == Y[0];

    for (int j = 1; j < X.size(); j++) {
      for (int k = 1; k < Y.size(); k++) {
        if (X[j] == Y[k]) {
          dp[j][k] = dp[j-1][k-1] + 1;
        } else {
          dp[j][k] = max(dp[j-1][k], dp[j][k-1]);
        }
      }
    }

    cout << dp[X.size()-1][Y.size()-1] << 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 i= 0; i <= n; i++){
        c[0][i] = 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<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
int p[1001][1001]={0};
int main(){
int i,j,q,e,l,z,m,u,n;
char s[2001],c[2001];
cin>>q;
for(e=0;e<q;e++){
scanf("%s %s",s,c);
l=strlen(s);
z=strlen(c);

for(i=0;i<=l;i++){
	for(j=0;j<=z;j++){
		p[i][j]=0;
	}
}
for(i=1;i<=z;i++){
	for(j=1;j<=l;j++){
		if(c[i-1]==s[j-1])p[j][i]=p[j-1][i-1]+1;
		else p[j][i]=max(p[j][i-1],p[j][i-1]);
	}
}
cout<<p[l][z]<<endl;
}
return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <algorithm>

#define SIZE 1002
int FTable[SIZE][SIZE];
class TLcsSolver
{
    const char* FArray1;
    const char* FArray2;
    const int Fn1;
    const int Fn2;

    int Count(int i, int j)
    {
        if(i == 0 || j == 0) return 0;
        if(FArray1[i-1] == FArray2[j-1]){
            return FTable[i-1][j-1] + 1;
        }
        return std::max(FTable[i-1][j], FTable[i][j-1]);
    }
    void Solve()
    {
        for(std::size_t i = 1; i < Fn1; ++i){
            for(std::size_t j = 1; j < Fn2; ++j){
                FTable[i][j] = Count(i, j);
            }
        }
    }
    void Print()const
    {
        for(std::size_t i = 0; i < Fn1; ++i){
            for(std::size_t j = 0; j < Fn2; ++j){
                printf("%d\t", FTable[i][j]);
            }
            printf("\n");
        }
    } 
public:
    TLcsSolver(const char* a, const char* b)
     : FArray1(a), FArray2(b)
     , Fn1(std::strlen(a)), Fn2(std::strlen(b))
    {
        Solve();
        // Print();
    }
    int Answer()const
    {
        return FTable[Fn1-1][Fn2-1];
    }
};

int main()
{
    int n;
    std::scanf("%d\n", &n);
    char a[SIZE];
    char b[SIZE];
    for(int i = 0; i < n; ++i){
        std::fgets(a, SIZE, stdin);
        std::fgets(b, SIZE, stdin);
        std::printf("%d\n", TLcsSolver(a, b).Answer());
    }
    return 0;
}

C++: #include<stdio.h>
#include<string.h>
 
#define MAX 1010
#define max(a,b) ((a<b)?b:a)
 
char s[MAX], t[MAX];
int dp[MAX][MAX],path[MAX][MAX];
 
int LCS() {
  int n = strlen(s);
  int m = strlen(t);
  memset(dp,0,sizeof dp);
  int i,j,maxi=0;
  for(i=0;i<n;i++) {
    for(j=0;j<m;j++) {
      if( i ) dp[i][j] = max(dp[i][j],dp[i-1][j]);
      if( j ) dp[i][j] = max(dp[i][j],dp[i][j-1]);
      if( s[i] == t[j] ) {
    dp[i+1][j+1] = max(dp[i+1][j+1],dp[i][j]+1);
    maxi = max(maxi,dp[i+1][j+1]);
      }
    }
  }
  return maxi;
}
 
int main() {
  int n,i;
  scanf("%d",&n);
  for(i=0;i<n;i++) {
  scanf(" %s",&s[0]);
  scanf(" %s",&t[0]);
  printf("%d\n",LCS());
  }
  return 0;
}

C++: n=int(input())
ans=[]
for k in range(n):
    s1=input()
    s2=input()
    dp=[[0 for i in range(len(s2)+1)] for j in range(len(s1)+1)]
    for i in range(1,len(s1)+1):
        for j in range(1,len(s2)+1):
            if s1[i-1]==s2[j-1]:
                dp[i][j]=dp[i-1][j-1]+1
            else:
                dp[i][j]=max(dp[i-1][j],dp[i][j-1])


    ans.append(dp[len(s1)][len(s2)])
for a in ans:
    print(a)