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<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 = 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 - 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>
??
int LCS(char x[], char y[]) {
????int xn = 0, yn = 0, flag = 0, i, j, max = 0;
????int c[1001][1001];
??????
????while (flag == 0)
????{
????????if (x[xn] != '\0')
????????{
????????????xn++;
????????}
????????else
????????{
????????????flag = 1;
????????}
????}
??????
????flag = 0;
??????
????while (flag == 0)
????{
????????if (y[yn] != '\0')
????????{
????????????yn++;
????????}
????????else
????????{
????????????flag = 1;
????????}
????}
????for (i = 1; i < xn + 1; i++) c[i][0] = 0;
????for (j = 1; j < yn + 1; j++) c[0][j] = 0;
??????
????for (i = 1; i < xn + 1; i++)
????{
????????for (j = 1; j < yn + 1; j++)
????????{
????????????if (x[i - 1] == y[j - 1])
????????????{
????????????????c[i][j] = c[i - 1][j - 1] + 1;
????????????}
????????????else if (c[i - 1][j] >= c[i][j - 1])
????????????{
????????????????c[i][j] = c[i - 1][j];
????????????}
????????????else
????????????{
????????????????c[i][j] = c[i][j - 1];
????????????}
????????????if (max < c[i][j]) max = c[i][j];
????????}
????}
??????
????return max;
}
??
int main(void) {
????char x[1000], y[1000];
????int q, i;
??????
????scanf("%d", &q);
??????
????for (i = 0; i < q; i++)
????{
????????scanf("%s", x);
????????scanf("%s", y);
????????printf("%d\n", LCS(x, y));
????}
??????
????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 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]);
      }
      maxl = max(maxl, c[i][j]);
    }
  }
  return maxl;
}

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

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

string a, b;
int q;
// iまで、jまででの答え
int dp[1005][1005] = {0};

int solve();

int main() {
  cin >> q;
  for(int qq = 0; qq < q; ++qq) {
    cin >> a >> b;
    cout << solve() << endl;
    for(int i = 1; i <= a.size(); ++i)
      for(int j = 1; j <= b.size(); ++j) dp[i][j] = 0;
  }
  return 0;
}

int solve() {
  for(int i = 1; i <= a.size(); ++i)
    for(int j = 1; j <= b.size(); ++j) {
      dp[i][j] =
          max(dp[i][j - 1],
              max(dp[i - 1][j - 1] + (a[i - 1] == b[j - 1]),
                  dp[i - 1][j]));
    }
  return dp[a.size()][b.size()];
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <set>
#include<algorithm>
#include <iomanip>
int ctoi(char c) {
	switch (c) {
	case '0': return 0;
	case '1': return 1;
	case '2': return 2;
	case '3': return 3;
	case '4': return 4;
	case '5': return 5;
	case '6': return 6;
	case '7': return 7;
	case '8': return 8;
	case '9': return 9;
	default: return 0;
	}
}
using namespace std;
typedef long long ll;
//定義場所//
int i, j, k, l, m, n;
int N, Q;
vector <int> Ans;
////////////

int main()
{
	int N;
	cin >> N;
	for (k = 0; k < N; k++) {
		vector<vector<int> >dp(1001, vector<int>(1001, 0));
		int ans = 0;
		string s1, s2;
		cin >> s1 >> s2;
		s1 = ' ' + s1;
		s2 = ' ' + s2;
		for (i = 0; i < s1.size(); i++) { dp[i][0] = 0; }
		for (i = 1; i < s2.size(); i++) { dp[0][i] = 0; }
		for (i = 1; i < s1.size(); i++) {
			for (j = 1; j < s2.size(); j++) {
				if (s1[i] == s2[j]) {
					dp[i][j] = dp[i - 1][j - 1] + 1;
				}
				else {
					dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
				}
				ans = max(ans, dp[i][j]);
			}
		}
		Ans.push_back(ans);
	}
	for (i = 0; i < Ans.size(); i++) {
		cout << Ans[i] << endl;
	}
}

C++: #include <iostream>
#include <string>
using namespace std;

int lcs(string X, string Y) {
  int cs[1001][1001];
  int m = X.size();
  int n = Y.size();
  int answer = 0;
  X = ' ' + X;
  Y = ' ' + Y;
  for (int i = 1; i <= m; i++) cs[i][0] = 0;
  for (int j = 1; j <= n; j++) cs[0][j] = 0;

  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (X[i] == Y[j]) {
        cs[i][j] = cs[i - 1][j - 1] + 1;
      } else {
        cs[i][j] = max(cs[i - 1][j], cs[i][j - 1]);
      }
      answer = max(answer, cs[i][j]);
    }
  }

  return answer;
}

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

  int n;
  cin >> n;

  string X, Y;

  for (int i = 0; i < n; i++) {
    cin >> X >> Y;
    cout << lcs(X, Y) << endl;
  }

  return 0;
}