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 <cstdio>
#include <cmath>
#define MAX 1002
using namespace std;

int Lcc(const char *X, const char *Y) {
    int lcc = 0;
    int dp[MAX][MAX];
    for (int i=0; i<MAX; i++)
        for (int j=0; j<MAX; j++) dp[i][j] = 0;

    int x=1, y=1;
    for (int i=0;;i++) {
        if (X[i] == ',') {x = i;break;}
        for (int j=0;;j++) {
            if (Y[j] == ',') {
                y = j;
                break;
            }
            if (Y[j] == ',') {
                y = j;
                break;
            } else {
                if (X[i] == Y[j]) {
                    dp[i+1][j+1] = fmax(dp[i][j] + 1, dp[i+1][j]);
                } else {
                    dp[i+1][j+1] = fmax(dp[i+1][j], dp[i][j+1]);
                }
            }
        }
    }
    return dp[x-1][y-1];
}

int
main()
{
    int q;
    scanf("%d", &q);
    for (int i=0; i<(q); i++) {
        char X[MAX], Y[MAX];
        for (int i=0; i<MAX; i++) {
            X[i] = ','; Y[i] = ',';
        }
        scanf(" %s", X);scanf(" %s", Y);
        int LCC = Lcc(X, Y);
        printf("%d\n", LCC);
    }
    return 0;
}

C++: #include <stdio.h>

int score[1010][1010];

int max2 (int a, int b){
  if (a >= b) return a;
  else return b;
}

int len_of_str(const char s[]){
  int num = 0;

  while(s[num]) num++;

  return num;
}


int main() {
  char a[1010];
  char b[1010];
  int datanum;
  scanf("%d",&datanum);
  for(int c = 0; c < datanum; c++){

  scanf("%999s",a);
  scanf("%999s",b);
  int num1 = len_of_str(a);
  int num2 = len_of_str(b);


  for(int i = num1; i > 0; i--) a[i] = a[i - 1];
  a[0] = ' ';
  for(int j = num2; j > 0; j--) b[j] = b[j - 1];
  b[0] = ' ';

  for(int i = 0; i <= num1; i++) score[i][0] = 0;
  for(int j = 0; j <= num2; j++) score[0][j] = 0;

  int maximum = 0;

  for(int i = 1; i<= num1; i++){
    for (int j = 1; j <= num2; j++){
      if (a[i] == b[j])score[i][j] = score[i-1][j-1] + 1;
      else max2(score[i][j-1],score[i-1][j]);
      maximum = max2(maximum,score[i][j]);
    }
  }

  printf("%d\n",maximum);
}
  return 0;
}

C++: #include <bits/stdc++.h>
#define INF 5000000000000000000
#define ll long long
#define pll pair<ll, ll>
using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  ll q;
  cin >> q;
  for (ll testcase = 0; testcase < q; ++testcase) {
    string a, b;
    cin >> a >> b;
    vector<vector<ll>> dp(a.size() + 1, vector<ll>(b.size() + 1, 0));
    for (ll i = 0; i < a.size(); ++i) {
      for (ll j = 0; j < b.size(); ++j) {
        if (a.at(i) == b.at(j)) {
          dp.at(i + 1).at(j + 1) = max(dp.at(i + 1).at(j + 1), dp.at(i).at(j) + 1);
        }
        dp.at(i + 1).at(j) = max(dp.at(i + 1).at(j), dp.at(i).at(j));
        dp.at(i).at(j + 1) = max(dp.at(i).at(j + 1), dp.at(i).at(j));
        dp.at(a.size()).at(j + 1) = max(dp.at(a.size()).at(j), dp.at(a.size()).at(j + 1));
      }
      dp.at(i + 1).at(b.size()) = max(dp.at(i + 1).at(b.size()), dp.at(i).at(b.size()));
    }
    cout << dp.at(a.size()).at(b.size()) << "\n";
    // for (ll i = 0; i <= a.size(); ++i) {
    //   for (ll j = 0; j <= b.size(); ++j) {
    //     cout << dp.at(i).at(j) << " ";
    //   }
    //   cout << "\n";
    // }
  }
}

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

int lcs(string X,string Y)
{
    int x=X.size(),y=Y.size();
    int dp[y+1][x+1];

    for(int i=0;i<x+1;i++)dp[0][i]=0;
    for(int i=1;i<y+1;i++)dp[i][0]=0;
    int maxl=0;
    
    for (int j = 1; j <= y; j++){
        for (int k = 1; k <= x ; k++){
            if (Y[j-1]==X[k-1]) dp[j][k]=dp[j-1][k-1]+1;
            else dp[j][k]=max(dp[j][k-1],dp[j-1][k]);
            maxl=max(maxl,dp[j][k]);
        }
    }
    return maxl;
}

int main()
{
    int q;
    cin>>q;
    string X,Y;
    for (int i = 0; i < q; i++) {
        cin>>X>>Y;
        cout<<lcs(X,Y)<<endl;
    }
}
/*
3
abcbdab
bdcaba
abc
abc
abc
bc
*/

C++: #include "stdio.h"
#include<iostream>
#include<string>
#include<algorithm>

#define MAX 1000

using namespace std;

int lcs(string input1, string input2){
  int m = input1.length();
  int n = input2.length(); 

  input1 = " " + input1;
  input2 = " " + input2; 

  //Singleton?
  int c[MAX+1][MAX+1];
    
  for(int i=0;i<=m;i++){
    c[i][0] = 0;
  }
  for(int j=0;j<=n;j++){
    c[0][j] = 0;
  }

  for(int i=1;i<=m;i++){
    for(int j=1;j<=n;j++){
      
      if(input1[i] == input2[j]){
        c[i][j] = c[i-1][j-1] + 1;
      }else{
        c[i][j] = max(c[i-1][j], c[i][j-1]);
      }
    
    }     
  }
  return c[m][n];
}

int main(void){
  
  int N;
  scanf("%d", &N);

  string  input1, input2;

  for(int i=0;i<N;i++){
    cin >> input1;
    cin >> input2;
    printf("%d\n", lcs(input1, input2));
  }

  return 0;
}