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;

int lcs(string X,string Y){
  int c[1001][1001];
  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;
}

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

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

using namespace std;

int q;
string A, B;

void findlongest() {
	int res[1001][1001];
	A = ' '+A ;
	B = ' '+B ;
	int l1 = A.size();
	int l2 = B.size();
	int max = 0;
	int j;
	for (int i = 0; i < l1; ++i) {
		for (j = 0; j < l2; ++j) {
			if (i == 0) {
				res[0][j] = 0;
			}
			else if (j == 0) {
				res[i][0] = 0;
			}
			else {
				if (A[i] == B[j]) {
					res[i][j] = res[i - 1][j - 1] + 1;
					if (max < res[i][j]) {
						max = res[i][j];
					}
				}
				else {
					if (res[i - 1][j] >= res[i][j - 1]) {
						res[i][j] = res[i - 1][j];
					}
					else {
						res[i][j] = res[i][j - 1];
					}
				}
			}
			//cout << res[i][j] << ' ';
		}
		//cout << endl;
	}

	cout << max << endl;
}

int main() {
	cin >> q;
	for (int i = 0; i < q; ++i) {
		cin >> A;
		cin >> B;
		findlongest();
	}
	return 0;
}

C++: #include<iostream>
#include<map>
#include<vector>
#include<algorithm>
#include<cmath>
#include<climits>
#include<ctime>
#include<cstring>
#include<numeric>

#define ALL(v) (v).begin(),(v).end()
#define REP(i,p,n) for(int i=p;i<(int)(n);++i)
#define rep(i,n) REP(i,0,n)
#define dump(a) (cerr << #a << "=" << (a) << endl)
#define DUMP(list) cout << "{ "; for(auto nth : list){ cout << nth << " "; } cout << "}" << endl;

using namespace std;

const int INF = 100000000;

int main() {
	int N;
	cin >> N;
	rep(i, N) {
		string s1, s2;
		cin >> s1 >> s2;
		int n = s1.size();
		int m = s2.size();
		vector<vector<int>> dp(n+1, vector<int>(m+1, 0));
		dp[0][0] = 0;
		for(int i = 1; i <= n; ++i) {
			for(int j = 1; j <= m; ++j) {
				if(s1[i-1] == s2[j-1]) {
					dp[i][j] = dp[i-1][j-1] + 1;
				} else {
					dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
				}	
			}
		}
		cout << dp[n][m] << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <climits>
#include <cmath>
#include <algorithm>
#include <utility>
#include <vector>
#include <string>

#define MAX 200000
#define INFTY 1<<30

using namespace std;

static const int N = 1000;

int lcs(string X, string Y)
{
  int dp[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++) dp[i][0] = 0;
  for(int j = 0; j < n; j++) dp[0][j] = 0;

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

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

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

int main(){
  int n;
  char x[1001],y[1001];
  int dp[1002][1002];
  


  //load n;
  cin >>n;
  for(int i=0;i<n;i++){
    //initialize
    for(int i=0;i<1002;i++){
      for(int j=0;j<1002;j++){
	dp[i][j]=0; 
      }
    }
    //load string
    scanf("%s",x);
    scanf("%s",y);
    //dp
    for(int j=0;j<strlen(x);j++){
      for(int k=0;k<strlen(y);k++){
	if(x[j]==y[k]){
	  dp[j+1][k+1]=dp[j][k]+1;
	}

	else{
 
	  if(dp[j][k+1]>dp[j+1][k]){
	    dp[j+1][k+1]=dp[j][k+1];
	  }

	  else{
	    dp[j+1][k+1]=dp[j+1][k];
	  }
	}
      }
    }

    //print
    cout <<dp[strlen(x)][strlen(y)]<<endl;
  }



  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <string>
using namespace std;
static const int N = 1000;
int C[N + 1][N + 1];

int lcs(string X, string Y)
{
	int m = X.size();
	int n = Y.size();
	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;

	int maxl = 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;
	}
}