Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	Q := sc.nextInt()
	for q := 0; q < Q; q++ {
		X, Y := sc.nextStr(), sc.nextStr()
		xLen, yLen := len(X), len(Y)
		dp := make([][]int, xLen+1)
		for i := 0; i <= xLen; i++ {
			dp[i] = make([]int, yLen+1)
		}
		for x := 0; x <= xLen; x++ {
			for y := 0; y <= yLen; y++ {
				if x == 0 || y == 0 {
					dp[x][y] = 0
				} else if X[x-1] == Y[y-1] {
					dp[x][y] = dp[x-1][y-1] + 1
				} else {
					dp[x][y] = max(dp[x-1][y], dp[x][y-1])
				}
			}
		}
		fmt.Fprintln(wtr, dp[xLen][yLen])
	}

	wtr.Flush()
}

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

int C[1001][1001];
string N1, N2;

int lcs()
{
	int m = N1.size();
	int n = N2.size();
	int maxl = 0;

	N1 = " " + N1;
	N2 = " " + N2;

	for (int i = 1; i <= m; i++)
		C[i][0] = 0;
	for (int i = 1; i <= n; i++)
		C[0][i] = 0;

	for (int i = 1; i <= m; i++)
	{
		for (int j = 1; j <= n; j++)
		{
			if (N1[i] == N2[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()
{
	ios::sync_with_stdio(false);
	cin.tie(0);

	int q;

	cin >> q;
	for (int i = 0; i < q; i++)
	{
		cin >> N1 >> N2;
		cout << lcs() << endl;
	}
		
	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], maxl = 0, i, j;
  int m = x.size();
  int n = y.size();

  x = ' ' + x;
  y = ' ' + y;
 
  for(i = 1; i <= m; i++) c[i][0] = 0;
  for(i = 1; i <= n; i++) c[0][i] = 0;

  for(i = 1; i <= m; i++){
    for(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 x, y;
  int q, i;

  cin >> q;
  
  for(i = 0; i < q; i++){
    cin >> x >> y;
    cout << lcs(x, y) << endl;
  }
  return 0;
}

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

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int q;
  cin >> q;
  for(int i = 0; i < q; i++) {
    string X, Y;
    cin >> X >> Y;
    vector<vector<int>> dp(X.size() + 1, vector<int>(Y.size() + 1));
    for(int i = 0; i < X.size(); i++) {
      dp[i][0] = 0;
    }
    for(int i = 0; i < Y.size(); i++) {
      dp[0][i] = 0;
    }
    for(int i = 0; i < X.size(); i++) {
      for(int j = 0; j < Y.size(); j++) {
        if(X[i] == Y[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]);
        }
      }
    }
    cout << dp[X.size()][Y.size()] << endl;
  }

  return 0;
}

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

using namespace std;

int main () {

    int N, m, n, i, j, k, c[1001][1001];
    string x, y;

    cin >> N;

    for (k = 0; k < n; k++) {
        cin >> x >> y;
        m = x.size ();
        n = y.size ();

        for (i = 1; i < m + 1; i++) {
            for (j = 1; j <= n + 1; 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]);
                }

            }
        }

    cout << c[m][n] << endl;

    }

}

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

using namespace std;

int main(int argc, char* argv[]) {
  int q;
  cin >> q;
  int rets[q];
  for (int i = 0; i < q; ++i) {
    string s, t;
    cin >> s >> t;

    int dp[s.size() + 1][t.size() + 1];
    memset(dp, 0, sizeof(int) * (s.size() + 1) * (t.size() + 1));

    for (int j = 0; j < s.size(); ++j) {
      for (int k = 0; k < t.size(); ++k) {
        if (s[j] == t[k])
          dp[j + 1][k + 1] = dp[j][k] + 1;
        else
          dp[j + 1][k + 1] = max(dp[j + 1][k], dp[j][k + 1]);
      }
    }

    rets[i] = dp[s.size()][t.size()];

  }

  for (int i = 0; i < q; ++i)
    cout << rets[i] << endl;

  return 0;
}

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

using namespace std;

void lcs(string x,string y){
  int m=x.length();
  int n=y.length();
  int c[m+1][n+1];
  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-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]);
      }
    }
  }
  cout << c[m][n] << endl;
}

int main(){
  int q;
  cin >> q;
  for(int i=0;i<q;i++){
    string x,y;
    cin >> x >> y;
    lcs(x,y);
  }
}