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>

int LCS(std::string str1, std::string str2, int i, int j){
  if(str1[i] == str2[j]){
    return 1;
  }
  else{
    return 0;
  }
}

int max(int a, int b, int c){
  int m = a;
  if(b > m){
    m = b;
  }
  if(c > m){
    m = c;
  }
  return m;
}

int main(){
  int q;
  std::cin >> q;
  //int ans[q];
  std::string str1, str2;
  for(int z=0; z<q; z++){
    std::cin >> str1 >> str2;
    int l1 = str1.size();
    int l2 = str2.size();
    int DP[l1+1][l2+1];

    for(int i=0; i<=l1; i++){
      DP[i][0] = 0;
    }
    for(int j=0; j<=l2; j++){
      DP[0][j] = 0;
    }

    for(int i=1; i<=l1; i++){
      for(int j=1; j<=l2; j++){
	DP[i][j] = max(DP[i-1][j], DP[i][j-1], DP[i-1][j-1] + LCS(str1, str2, i-1, j-1));
      }
    }
    //ans[z] = DP[l1][l2];
    std::cout << DP[l1][l2] << std::endl;
  }

  /*for(int z=0; z<q; z++){
    std::cout << ans[z] << std::endl;
    }*/
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)

int lcs(string x, string y) {
    x = ' ' + x;
    y = ' ' + y;
    int m = x.size();
    int n = y.size();
    vector<vector<int>> c(m, vector<int>(n, 0));
    rep(i, m) {
        rep(j, n) {
            if (i == 0 || j == 0) continue;
            if (x[i] == y[j]) c[i][j] = c[i-1][j-1] + 1;
            else c[i][j] = max(c[i][j-1], c[i-1][j]);
        }
    }
    return c[m-1][n-1];
}

int main() {
    int n;
    cin >> n;
    rep(i, n) {
        string s1, s2;
        cin >> s1;
        cin >> s2;
        cout << lcs(s1, s2) << endl;
    }
}

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

string X;
string Y;

int calc(int x, int y, vector<vector<int> >& Memo){
    if (X[x] == '\0' || Y[y] == '\0') return 0;
    if (Memo[x][y] != -1) return Memo[x][y];

    int unuse = calc(x + 1, y, Memo);
    int use = 0;
    int y_target = Y.find(X[x], y);
    if (y_target == string::npos) {
        use = 0;
    } else {
        use = calc(x + 1, y_target + 1, Memo) + 1;
    }
    return Memo[x][y] = max(unuse, use);
}

int main(){
    int q;
    cin >> q;
    for (int i = 0; i < q; i++) {
        cin >> X;
        cin >> Y;
        vector<int> tmp(Y.size(), -1);
        vector<vector<int> > Memo(X.size(), tmp);
        cout << calc(0, 0, Memo) << endl;
    }

    return 0;
}

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

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

    int max_len = 0;
    for (int i = 1; i <= m; i++) {
        for (int 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] = max(c[i - 1][j], c[i][j - 1]);
            }
            max_len = max(max_len, c[i][j]);
        }
    }

    return max_len;
}

int main() {
    int n;
    cin >> n;
    string s1, s2;
    int max_len[n];
    for (int i = 0; i < n; i++) {
        cin >> s1 >> s2;
        max_len[i] = lcs(s1, s2);
    }

    for (int i = 0; i < n; i++) {
        cout << max_len[i] << endl;
    }

    return 0;
}

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


int LCS(const string& a, const string& b) {
    int ans = 0;
    const int len_a = a.length(), len_b = b.length();

    int dp[len_a + 1][len_b + 1] = {};
    for(int i=1; i<=len_a; i++) {
	for(int j=1; j<=len_b; j++) {
	    dp[i][j] = max(dp[i][j], dp[i-1][j] );
	    dp[i][j] = max(dp[i][j], dp[i][j-1] );
	    dp[i][j] = max(dp[i][j], dp[i-1][j-1] + (a[i-1] == b[j-1] ? 1 : 0) );
	}
    }
    ans = dp[len_a][len_b];
    return ans;
}

int main() {

    int N;
    cin >> N;

    for(int i=0; i<N; i++) {
	string a,b;
	cin >> a >> b;
	cout << LCS(a,b) << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#define N 1000
using namespace std;
 
int lcs(string S1,string S2){
    int c[N+1][N+1];
    int S1_size = S1.size();
    int S2_size = S2.size();
     
    for(int i=1;i<S1_size;i++) c[i][0] = 0;
    for(int i=1;i<S2_size;i++) c[0][i] = 0;
     
    S1 = ' '+S1;
    S2 = ' '+S2;
     
    int max_lcs=0;
    for(int j=1;j<=S1_size;j++){
        for(int k=1;k<=S2_size;k++){
            if(S1[j]==S2[k]){
                c[j][k] = c[j-1][k-1] + 1;
            }else{
                c[j][k] = max(c[j-1][k],c[j][k-1]);
            }
            max_lcs = max(max_lcs,c[j][k]);
        }
    }
    return max_lcs;
}
 
int main() {
    // your code goes here
    int q;
    string str1,str2;
    cin>>q;
    for(int i=0;i<q;i++){
        cin>>str1>>str2;
        cout<<lcs(str1,str2)<<endl;
    }
    return 0;
}

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

int Max(int &a,int b){return a=max(a,b);}

int LCS(string &a,string &b){
  int n = a.size();
  int m = b.size();
  vector <vector<int> > dp(n+1,vector<int>(m+1));

  for(int i=0;i<=n;i++)
    for(int j=0;j<=m;j++){
      if(i<n && j<m && a[i] == b[j]) Max(dp[i+1][j+1],dp[i][j]+1);
      if(i<n)Max(dp[i+1][j],dp[i][j]);
      if(j<m)Max(dp[i][j+1],dp[i][j]);

    }
  return dp[n][m];
}

int main(){
  int q;
  cin>>q;
  while(q--){
    string a,b;
    cin>>a>>b;
    cout<<LCS(a,b)<<endl;
  }
  return 0;
}