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<stdio.h>

int hantei(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] >= 97 && x[xn] <= 122)
    {
      xn++;
    }
    else
    {
      flag = 1;
    }
  }
  
  flag = 0;
  
  while (flag == 0)
  {
    if (y[yn] >= 97 && y[yn] <= 122)
    {
      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", hantei(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();
    x = ' ' + x;
    y = ' ' + y;
    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 (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]);
            }
        }
    }

    return c[m][n];
}

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

C++: #include <iostream>
#include<string>
using namespace std;
int main(void){
    // Your code here!
    // Your code here!
    int q;
    cin>>q;
    string x[q],y[q];
   
    //string s[q*2];
    string tmp;
    for(int i=0;i<q;i++){
        cin>>tmp;
        x[i]=tmp;
        cin>>tmp;
        y[i]=tmp;
    }
    for(int i=0;i<q;i++){
        //cout<<sizeof(x)/sizeof(x[0])<<" "<<sizeof(y[i])<<"\n";
        int dp[x[i].length()+1][y[i].length()+1];
        for(int j=0;j<x[i].length()+1;j++){ 
            for(int k=0;k<y[i].length()+1;k++){ 
                if(j==0 || k==0){
                    dp[j][k]=0;
                }
                else if(x[i][j-1]==y[i][k-1]){
                    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[i].length()][y[i].length()]<<"\n";
    }
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;
int main() {
	int n;
	cin >> n;
	vector<int> ans(n);
	for (int cou = 0;cou < n;cou++) {
		string s, t;
		cin >> s >> t;
		int S = s.size(), T = t.size();
		vector<vector<int> > dp(S + 1, vector<int>(T + 1, 0));
		for (int i = 0;i < S;i++) {
			for (int j = 0;j < T;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]);
				}
			}
		}
		ans[cou] = dp[S][T];
	}
	for (int i = 0;i < n;i++) {
		cout << ans[i] << endl;
	}
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
// #define int long long

template <class T>
bool INRANGE(T x, T a, T b) { return a <= x && x <= b; }
template <class T>
inline bool chmin(T &a, T b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}
template <class T>
inline bool chmax(T &a, T b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define RREP(i, n) for (int i = (n); i >= 0; --i)
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define RFOR(i, a, b) for (int i = (a); i >= (b); --i)
#define ALL(v) (v).begin(), (v).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" \
                      << " " << __FILE__ << endl;

typedef vector<int> vi;
typedef vector<string> vs;
typedef vector<vi> vvi;
typedef pair<int, int> pii;

vvi dp;
string gx, gy;
int dfs(int ix, int iy) {
    if (ix == gx.length() or iy == gy.length()) {
        return 0;
    }
    if (dp[ix][iy] != -1) return dp[ix][iy];

    if (gx[ix] != gy[iy]) {
        int c1 = dfs(ix+1, iy);
        int c2 = dfs(ix, iy+1);
        dp[ix][iy] = max(c1, c2);
    } else {
        int c1 = dfs(ix+1, iy+1)+1;
        int c2 = dfs(ix, iy+1);
        dp[ix][iy] = max(c1, c2);
    }

    return dp[ix][iy];
}

void solve(string x, string y) {
    gx = x, gy = y;
    dp = vvi(1005, vi(1000, -1));
    cout << dfs(0, 0) << endl;
}

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

    int n;
    cin >> n;
    REP(i, n) {
        string x, y;
        cin >> x >> y;
        solve(x, y);
    }

    return 0;
}