Go: package main

import (
	"bufio"
	"os"
	"io"
	"strconv"
	"math"
	"fmt"
)

var (
	nstr   func() string
	stdout *bufio.Writer
)

func init() {
	nstr = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func main() {
	defer stdout.Flush()

	n := nint()
	xList := make([]string, n)
	yList := make([]string, n)

	for i:=0;i<n ;i++  {
		xList[i] = nstr()
		yList[i] = nstr()
	}

	for i := 0; i<n	; i++  {
		fmt.Println(lcs(xList[i], yList[i]))
	}

}

func lcs(x string, y string) int{
	var m = len(x)
	var n = len(y)

	c := make([][]int, m+1)
	for i:= range c{
		c[i] = make([]int, n+1)
	}
	for i:=	1;i<=m ;i++  {
		for j:=1;j<=n ;j++  {
			if x[i-1] == y[j-1]{
				c[i][j] = c[i-1][j-1] + 1
			}else{
				c[i][j] = int(math.Max(float64(c[i-1][j]), float64(c[i][j-1])))
			}


		}
	}
	return c[m][n]

}


func newReadString(ior io.Reader) func() string {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)

	return func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
}

func nint64() int64 {
	i, err := strconv.ParseInt(nstr(), 0, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func nint() int {
	return int(nint64())
}

func getIntSlice(n int) []int {
	b := make([]int, n)
	for i := 0; i < n; i++ {
		b[i] = nint()
	}
	return b
}

func getStringSlice(n int) []string {
	b := make([]string, n)
	for i := 0; i < n; i++ {
		b[i] = nstr()
	}
	return b
}

func gcd(x, y int) int {
	if y == 0 {
		return x
	}
	return gcd(y, x%y)
}

func lcm(x, y int) int {
	return x * y / gcd(x, y)
}

func contains(s []int, e int) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func bin(i int, prefix bool) string {
	i64 := int64(i)

	if prefix {
		return "0b" + strconv.FormatInt(i64, 2)
	} else {
		return strconv.FormatInt(i64, 2)
	}
}

func strReverse(s string) string {
	runes := []rune(s)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}

	return string(runes)
}

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

using namespace std;

#define FOR(i,s,e) for((i)=(s);(i)<(int)(e);(i)++)
#define REP(i,e) FOR(i,0,e)

#define all(o) (o).begin(), (o).end()
#define psb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))

typedef long long ll;
typedef pair<int, int> PII;

const double EPS = 1e-10;

const int N = 1000;
char s[N+1], t[N+1];
int ls, lt;
int q;
int dp[N+1][N+1];
//dp[i][j] = s[0]...s[i-1]??¨t[0]...t[j-1]???LCS
//(1<=i<=ls, 1<=j<=lt)

int main() {
  int i, j, k;
  scanf("%d ", &q);
  for (k=0; k<q; k++) {
    ls = lt = 0;
    memset(s, 0, sizeof(s)), scanf("%s ", s);
    memset(t, 0, sizeof(t)), scanf("%s ", t);
    while (s[ls]) ls++;
    while (t[lt]) lt++;

    memset(dp, 0, sizeof(dp));
    for (i=1; i<=ls; i++)
      for (j=1; j<=lt; j++) {
        if (s[i-1]==t[j-1])
          dp[i][j] = dp[i-1][j-1] + 1;
        else
          dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
      }

    printf("%d\n", dp[ls][lt]);
  }

  return 0;
}

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

static const int N = 1000;

int lcs(std::string X, std::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.at(i) == Y.at(j))
            {
                c[i][j] = c[i - 1][j - 1] + 1;
            }
            else
            {
                c[i][j] = std::max(c[i-1][j],c[i][j-1]) ;
            }
            maxl = std::max(maxl,c[i][j]) ;
        }
    }
    return maxl ;
}

int main()
{
    std::string s1,s2 ;
    int n;
    std::cin >> n ;
    for (int i = 0; i < n; i++)
    {
        std::cin >> s1 >> s2 ;
        std::cout << lcs(s1,s2) << std::endl ;
    }
    return 0 ;
}

C++: #include <stdio.h>
#include <iostream>
#include <algorithm>
??
using namespace std;
??
short checkTable[1001][1001];
??
int tmp_max=0;
??
??
void calc(int index,char pattern[],char to_search[],int to_search_length){
??
????????for(int i=to_search_length-1;i>=0;i--){
????????????????if(to_search[i]==pattern[index]){
????????????????????????checkTable[index][i]=1;
????????????????????????if(pattern[index+1]!='\0' && i < to_search_length-1){
????????????????????????????????checkTable[index][i] = checkTable[index+1][i+1] + checkTable[index][i];
????????????????????????}
????????????????}else{
????????????????????????if(i != to_search_length-1){
????????????????????????????????if(pattern[index+1] != '\0'){
????????????????????????????????????????checkTable[index][i]=(checkTable[index+1][i]>checkTable[index][i+1])
?????????????????????????????????????????????????????????checkTable[index+1][i]:checkTable[index][i+1];
??
????????????????????????????????}else{
????????????????????????????????????????checkTable[index][i]=(checkTable[index][i+1]>0)?checkTable[index][i+1]:0;
????????????????????????????????}
????????????????????????}else{
????????????????????????????????if(pattern[index+1] != '\0'){
????????????????????????????????????????checkTable[index][i]=(checkTable[index+1][i]>0)?checkTable[index+1][i]:0;
????????????????????????????????}else{
????????????????????????????????????????checkTable[index][i] = 0;
????????????????????????????????}
????????????????????????}
????????????????}
????????????????tmp_max = (tmp_max >= checkTable[index][i])?tmp_max:checkTable[index][i];
????????}
}
??
int main(){
??
????????int q,left_length,right_length;
????????char left[1001],right[1001];
??
????????scanf("%d",&q);
??
????????for(int i=0;i<q;i++){
????????????????left_length=0;
????????????????right_length=0;
????????????????scanf("%s %s",left,right);
????????????????for(int k=0;left[k]!='\0';k++)left_length++;
????????????????for(int k=0;right[k]!='\0';k++)right_length++;
??
????????????????if(right_length>=left_length){
??
????????????????????????for(int k=left_length-1;k>=0;k--)calc(k,left,right,right_length);
????????????????}else{
??
????????????????????????for(int k=right_length-1;k>=0;k--)calc(k,right,left,left_length);
????????????????}
????????????????printf("%d\n",tmp_max);
????????????????tmp_max=0;
????????}
??
????????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 res = 0;
	X = ' ' + X;
	Y = ' ' + Y;
	for (int i = 0;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 - 1][j], c[i][j - 1]);

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

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 <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#define FOR(i,b,e) for(int i=b;i<e;i++)
#define REP(i,n) FOR(i,0,n)
using namespace std;

string s1, s2;

int lcs(int n1, int n2) {
  if (n1 < 0 || n2 < 0) return 0;
  
  if (s1[n1] == s2[n2]) return 1 + lcs(n1 - 1, n2 - 1);
  else return max(lcs(n1, n2 - 1), lcs(n1 - 1, n2));
}

int main() {
	cin.tie(0);
 	ios::sync_with_stdio(false);

  int q; cin >> q;
  REP(i, q) {
    cin >> s1;
    cin >> s2;

    cout << lcs(s1.length() - 1, s2.length() - 1) << endl;
  }
}