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 main()
{
  int n;
  int an[1000];
  int l=0;
  std::cin>>n;
  std::string x;
  std::string y;
  int ans[1001][1001];
  int j,k;
  for(int i=0;i<n;i++){
    std::cin>>x;
    std::cin>>y;
    for(int j=0;j<=1000;j++){
      for(int k=0;k<=1000;k++){
	ans[j][k]=0;
      }
    }
    for(int j=1;j<=x.size();j++){
      for(int k=1;k<=y.size();k++){
	if(x[j]==y[k]){
	  ans[j][k]=ans[j-1][k-1]+1;
	}else{
	  if(ans[j][k-1]>ans[j-1][k]){
	    ans[j][k]=ans[j][k-1];
	  }else{
	    ans[j][k]=ans[j-1][k];
	  }
	}
      }
    }
    std::cout<<ans[x.size()-1][y.size()-1]<<'\n';  
  }
  return 0;
}

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

static int lc[1000][1000];
static std::string X, Y;

int count(int idx_x, int idx_y) {
    if (lc[idx_x][idx_y] != -1) {
        return lc[idx_x][idx_y];
    }

    int maximum = 0;
    
    if (X[idx_x] == Y[idx_y]) {
        if (idx_x > 0 && idx_y > 0) {
            maximum = std::max(maximum, count(idx_x - 1, idx_y - 1));
        }
        lc[idx_x][idx_y] = maximum + 1;
    } else {
        if (idx_x > 0) {
            maximum = std::max(maximum, count(idx_x - 1, idx_y));
        }
        if (idx_y > 0) {
            maximum = std::max(maximum, count(idx_x, idx_y - 1));
        }
        lc[idx_x][idx_y] = maximum;
    }
    return lc[idx_x][idx_y];
}

int LongestCommon() {
    for (int i = 0; i < X.length(); i++) {
        for (int j = 0; j < Y.length(); j++) {
            lc[i][j] = -1;
        }
    }
    return count(X.length() - 1, Y.length() - 1);
}

int main() {
    int q;
    std::cin >> q;
    for (int i = 0; i < q; i++) {
        std::cin >> X >> Y;
        std::cout << LongestCommon() << std::endl;
    }
}

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;


int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  int N, al, bl;
  string k, l;
  int ans[1001][1001];
  cin >> N;

  rep(i, N){
    cin >> k;
    cin >> l;

    al = k.length();
    bl = l.length();


    rep(j, al+1){
      rep(s, bl+1){
        ans[j][s] = 0;
      }
    }

    rep(j, al){
      rep(s, bl){
        if(k[j] == l[s]){
          ans[j+1][s+1] = max(ans[j+1][s], max(ans[j][s+1], ans[j][s] + 1));
        } else{
          ans[j+1][s+1] = max(ans[j+1][s], ans[j][s+1]);
        }
      }
    }

    cout << ans[al][bl] << "\n";



  }
}

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

int dp[1001][1001];
int main() {
	int b;
	scanf("%d", &b);
	char e[1001];
	char f[1001];
	for (int c = 0; c < b; c++) {
		scanf("%s%s", e, f);
		for (int g = 0; g <= strlen(e); g++) {
			for (int h = 0; h <= strlen(f); h++) {
				dp[g][h] = 0;
			}
		}
		for (int g = 1; g <= strlen(e); g++) {
			for (int h = 1; h <= strlen(f); h++) {
				if (e[g] == f[h]) {
					dp[g][h] = dp[g - 1][h - 1] + 1;
				}
				else {
					dp[g][h] = max(dp[g][h - 1], dp[g - 1][h]);
				}
			}
		}
		printf("%d\n", dp[strlen(e)][strlen(f)]);
	}
}

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

#define ll long long
#define vvi vector<vector<int>>
#define vec vector
#define pq priority_queue
#define all(v) (v).begin(), (v).end()
#define uniqueV(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
#define rep(i, n) for (int (i) = (0); (i) < (n); ++(i))
#define repp(i, m, n) for (int (i) = (m); (i) < (n); ++(i))
#define dbg(x) cerr << #x << ": " << x << endl;
#define dbg2(x, y) cerr<<"("<<#x<<", "<<#y<<") = "<<"("<<x<<", "<<y<<")"<<endl;
#define dbg3(x, y, z) cerr<<"("<<#x<<", "<<#y<<", "<<#z<<") = "<<"("<<x<<", "<<y<<", "<<z<<")"<<endl;
#define dbgB(value, size) cerr<<#value<<": "<<bitset<size>(value) << endl;
#define line() cerr << "---------------" << endl;

const int dx[] = {1, -1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const double PI = 3.14159265358979323846;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }

template<typename T>
void printA(vector<T> &printArray, char between = ' ') {
   int paSize = printArray.size();
   for (int i = 0; i < paSize; i++) { cerr << printArray[i] << between;}
   if (between != '\n') {cerr << endl;}
}

// ------------------------------------------------------------------------------------------

int q;
string x, y;
int dp[1111][1111];

void solve() {
   for (int i = 1; i <= x.size(); i++) {
      for (int j = 1; j <= y.size(); 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]);
         }
      }
   }
   cout << dp[x.size()][y.size()] << endl;
}

int main() {
   cin >> q;
   while (q--) {
      fill(dp[0], dp[1111], 0);
      cin >> x >> y;
      solve();
   }

   return 0;
}