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 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; 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] = max (c[i - 1][j], c[i][j - 1]);
                }

            }
        }

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

    }

}

C++: #include<stdio.h>
#include<string>
#include<algorithm>
using namespase 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();
  int maxl = 0;
  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;

  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;
  }
  
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define N 1050
int lcs(string X,string Y){
  int c[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++) 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<stdlib.h>
#include<cstdio>
#include<math.h>
#include<algorithm>
#include<string.h>
#include<string>

#define Max 1005
using namespace std;

int N;

int Long(string A, string B)
{
	int a = A.length();
	int b = B.length();
	int L[Max][Max];
	int maxi = 0;
	for (int i = 0; i < a; i++)
	{
		L[i][0] = 0;
	}

	for (int i = 0; i < b; i++)
	{
		L[0][i] = 0;
	}

	for (int i = 1; i < a; i++)
	{
		for (int j = 1; j < b; j++)
		{
			if (A[i] == B[j])
				L[i][j] = L[i - 1][j - 1] + 1;
			else
				L[i][j] = max(L[i - 1][j], L[i][j - 1]);
			maxi = max(maxi, L[i][j]);
		}
	}
	return maxi;
}

int main()
{
	int n;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		string A;
		string B;
		cin >> A;
		A = ' ' + A;
		cin >> B;
		B = ' ' + B;
		cout << Long(A, B) << endl;
	}
	return 0;
}

C++: #include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<iostream>
using namespace std;

#define N_MAX 1000

char X[N_MAX];
char Y[N_MAX];
int LCS[N_MAX+1][N_MAX+1];


int longest(int x, int y)
{
    for (int i = 0; i < x+1; i++) {
        for (int j = 0; j < y+1; j++) {
            if (i == 0 || j == 0) {
                LCS[i][j] = 0;
//                printf("0 LCS[%d][%d] = %d\n", i, j, LCS[i][j]);
            }
            else if (X[i-1] == Y[j-1]) {
                LCS[i][j] = LCS[i-1][j-1] + 1;
//                printf("1 LCS[%d][%d] = %d\n", i, j, LCS[i][j]);
            }
            else {
                LCS[i][j] = (LCS[i-1][j] > LCS[i][j-1]) ? LCS[i-1][j] : LCS[i][j-1]; 
//                printf("LCS[%d][%d] = %d\n", i, j, LCS[i][j]);
            }
        }
    }

    return LCS[x][y]; 
}

int main() {
    int q;
    int x;
    int y;

    cin >> q;

    for (int i = 0; i < q; i++) {
        scanf("%s", X);
        x = strlen(X);
        scanf("%s", Y);
        y = strlen(Y);
        cout << longest(x, y) << endl;
    }
        
    return 0;
}

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

int lcs(string str1, string str2)
{
	int len[1001][1001] = { 0 };

	int len1 = str1.length();
	int len2 = str2.length();
	str1 = ' ' + str1;
	str2 = ' ' + str2;

	for (int i = 0; i <= len1; i++)
		for (int j = 0; j <= len2; j++) len[i][j] = 0;

	for (int i = 1; i <= len1; i++)
	{
		for (int j = 1; j <= len2; j++)
		{
			if (str1[i] == str2[j]) len[i][j] = len[i - 1][j - 1] + 1;
			else len[i][j] = max(len[i - 1][j], len[i][j - 1]);
		}
	}
	return len[len1][len2];
}

int main()
{
	int n;
	string str1, str2;

	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> str1 >> str2;
		cout << lcs(str1, str2) << endl;
	}

	return 0;
}

C++: #include<cstdio>
#include<iostream>
#include<algorithm>
#include<string.h>
using namespace std;
int dp[1001][1001] = { 0 };
int main()
{
	int sy,sx, q, k;
	char x[2001], y[2001];
	k = 0;
	scanf("%d", &q);
	for (int z = 0; z < q; z++)
	{
		if (z != 0)
		{
			for (int i = 1; i <= sy; i++)
			{
				for (int j = 1; j <= sx; j++)
					dp[i][j] = 0;
			}
		}
		scanf("%s %s", x, y);
		sx = strlen(x);
		sy = strlen(y);
		for (int i = 1; i <= sy; i++)
		{
			for (int j = 1; j <= sx; j++)
			{
				if (y[i - 1] == x[j - 1])
					dp[i][j] += dp[i - 1][j - 1] + 1;
				else
					dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
			}
		}
		printf("%d\n", dp[sy][sx]);
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define For(I,A,B) for(int I=(A); I < (B); ++I)
int main()
{
int t;
cin>>t;
while(t--){
int a[1000]={0},b[1000]={0},c[200][200];
int x,y,z,k=0,l,i,j;

 For(i,0,200)
 For(j,0,200)
 c[i][j]=0;


 cin>>x>>y;
 For(i,0,x+1)
 For(j,0,y+1)
 c[i][j]=0;
 For(i,1,x+1) cin>>a[i];
 For(i,1,y+1) cin>>b[i];

 For(i,1,x+1)
 For(j,1,y+1)
 {
     if(a[i]==b[j]) c[i][j]=c[i-1][j-1]+1;
     else  c[i][j]=max(c[i-1][j],c[i][j-1]);
 }
    cout<<c[x][y]<<endl;

}
}
    return 0;
}