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

int lengthOfLcs_r(const char x[], const char y[], int ix, int iy, int xsize, int ysize, int **lengthTable) {
	if (ix == xsize || iy == ysize) {
		return 0;
	}
	if (lengthTable[ix][iy] != -1) {
		return lengthTable[ix][iy];
	}
	if (x[ix] == y[iy]) {
		return lengthTable[ix][iy] = lengthOfLcs_r(x, y, ix + 1, iy + 1, xsize, ysize, lengthTable) + 1;
	}
	return lengthTable[ix][iy] = max(lengthOfLcs_r(x, y, ix, iy + 1, xsize, ysize, lengthTable), lengthOfLcs_r(x, y, ix + 1, iy, xsize, ysize, lengthTable));
}

int lengthOfLcs(string x, string y) {
	int xsize = x.size(), ysize = y.size();

	int **lengthTable = new int*[xsize];
	for (int i = 0; i < xsize; ++i) {
		lengthTable[i] = new int[ysize];
		fill_n(lengthTable[i], ysize, -1);
	}

	int ret = lengthOfLcs_r(x.c_str(), y.c_str(), 0, 0, xsize, ysize, lengthTable);
	
	for (int i = 0; i < xsize; i++) {
		delete[] lengthTable[i];
	}
	delete[] lengthTable;
	
	return ret;
}

int main() {
	int q;
	string x, y;

	cin >> q;
	for (int i = 0; i < q; ++i) {
		cin >> x >> y;
		cout << lengthOfLcs(x, y) << endl;
	}
	return 0;
}

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

#define MAX_S 1010
#define MAX_T 1010

template<typename T> int lcs(T s,T t){
    int lens=s.size();
    int lent=t.size();
    int dp[MAX_S+1][MAX_T+1]={};
    
    
    for(int i=0;i<lens;i++){
        for(int j=0;j<lent;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]);
        }
    }
    return dp[lens][lent];
}

int main(){
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        string s,t;
        cin>>s>>t;
        cout<<lcs(s,t)<<endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;

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

int solve(string d1, string d2) {
  int m = d1.size(), n = d2.size();
  vvi c(m + 1, vi(n + 1));
  d1 = " " + d1;
  d2 = " " + d2;
  
  int l = 0;
  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (d1[i] == d2[j]) c[i][j] = c[i - 1][j - 1] + 1;
      else c[i][j] = max(c[i - 1][j], c[i][j - 1]);

      l = max(l, c[i][j]);
    }
  }

  return l;
}

int main() {
  int q;
  cin >> q;
  
  rep(i, q) {
    string d1, d2;
    cin >> d1 >> d2;
    cout << solve(d1, d2) << endl;
  }
}

C++: #include <bits/stdc++.h>
typedef long long ll;
#define ALL(l)  (l).begin(),(l).end()
#define rep(i,n) for(ll (i)=0;(i)<(n);(i)++)
#define rep2(i, s, n) for (ll i = (s); i < (ll)(n); i++)
using namespace std;

//const ll mod =  1000000007;
//const ll maxn = 1000000000;

//---------------------------------------------------------------------------------------------------
using vi = vector<int>; // intの1次元の型に vi という別名をつける
using vll = vector<ll>; // intの1次元の型に vi という別名をつける
using vvll = vector<vll>; // intの2次元の型に vvi という別名をつける
using vs = vector<string>; // stringの1次元の型に vs という別名をつける
using pll = pair<ll, ll>; // これ以降 pii という型名はpair<ll, ll> と同じ意味で使える
//---------------------------------------------------------------------------------------------------


int main() {
    int n;
    cin>>n;
    rep(i,n){
        string s1,s2;
        cin>>s1>>s2;
        
        
        vvll dp(s1.size()+1,vll(s2.size()+1));
        
        rep(i,s1.size()){
            dp.at(i).at(0)=0;
            rep(j,s2.size()){
                dp.at(0).at(j)=0;
                if(s1.at(i)==s2.at(j)){
                    dp.at(i+1).at(j+1)=(dp.at(i).at(j)+1);//,dp.at(i).at(j+1)+1);
                }else{
                    dp.at(i+1).at(j+1)=max(dp.at(i+1).at(j),dp.at(i).at(j+1));
                }
            }
        }
        cout<<dp.at(s1.size()).at(s2.size())<<endl;
    }
    
}

C++: #include <stdio.h>
#include <string.h>
#define rep(i, n) for(int i = 0; i < n; ++i)
#define repi(i, n) for(int i = 1; i < n; ++i)

int max(int a, int b) {
  return a > b ? a : b;
}

int main(void) {
  int n;
  scanf("%d", &n);
  rep(i, n) {
    char x[1500], y[1500], h, w;
    scanf("%s", x);
    scanf("%s", y);
    h = strlen(x), w = strlen(y);
    int dp[h][w], len[w], maxs = 0;
    rep(j, h) rep(k, w) dp[j][k] = 0;
    rep(j, w) if(x[0] == y[j]) dp[0][j] = 1, maxs = 1;
    len[0] = 0;
    repi(j, w) len[j] = max(dp[0][j - 1], len[j - 1]);
    repi(j, h) {
      rep(k, w) if(x[j] == y[k]) {
        dp[j][k] = len[k] + 1;
        if(maxs < dp[j][k]) maxs = dp[j][k];
      }
      repi(k, w) len[k] = max(dp[j][k - 1], max(len[k], len[k - 1]));
      /*rep(k, w) printf("%d ", len[k]);
      printf("\n");*/
    }
    /*printf("\n");
    rep(j, h) {
      rep(k, w) printf("%d ", dp[j][k]);
      printf("\n");
    }*/
    printf("%d\n", maxs);
  }
  return 0;
}