Go: package main

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

//Util
func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func maxInt(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func minInt(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

func absInt(a int) int {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func absFloat64(a float64) float64 {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func minFloat64(a, b float64) float64 {
	if a > b {
		return b
	} else {
		return a
	}
}

func str2Int(s string) int {
	n, _ := strconv.Atoi(s)
	return n
}

//Main
var sc = bufio.NewScanner(os.Stdin)
var q int
var X, Y string

func lcs(X, Y string) int {
	lenX := len(X)
	lenY := len(Y)
	dp := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		dp[i] = make([]int, lenY+1)
	}

	res := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if X[i-1] == Y[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
			//fmt.Println(dp)
			res = maxInt(res, dp[i][j])
		}

	}
	return res
}

func main() {
	sc.Split(bufio.ScanWords)
	q = nextInt()

	for i := 0; i < q; i++ {
		X = nextStr()
		Y = nextStr()

		fmt.Println(lcs(X, Y))
	}
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <set>
#include <algorithm>
#include <array>
#include <complex>
#include <utility>
#include <map>
#include <inttypes.h>
int c[1001][1001] = {0};
int LCS(std::string s, std::string t){
    int n, m;
    n = s.size();
    m = t.size();
    int maxlen = 0;
    for(int i = 1; i <= n; i++){
        c[i][0] = 0;
    }
    for(int i = 1; i <= m; i++){
        c[0][i] = 0;
    }
    for(int i = 1; i <= n; i++){
        for(int j = 1; j <= m; j++){
            if(s[i - 1] == t[j - 1]){
                c[i][j] = c[i - 1][j - 1] + 1;
            }
            else{
                c[i][j] = std::max(c[i - 1][j], c[i][j - 1]);
            }
            maxlen = std::max(maxlen, c[i][j]);
        }
    }
    return maxlen;
}
int main(){
    int N;

    std::cin >> N;
    std::string s1, s2;
    for(int i = 0; i<N; i++){
        std::cin >> s1 >> s2;
       
        std::cout << LCS(s1,s2) << std::endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <set>
#include <cmath>
#include <algorithm>
#include <iomanip>
#include <queue>
using ll = long long;
using namespace std;

int const MOD = 1e9 + 7;
int main(void)
{
    int N;
    cin >> N;
    for (int i = 0; i < N; ++i)
    {
        string s, t;
        cin >> s >> t;

        int dp[1010][1010];
        for (int i = 0; i < 1010; ++i)
            for (int j = 0; j < 1010; ++j)
                dp[i][j] = 0;

        int n = s.size();
        int m = t.size();

        for (int i = 0; i < n; ++i)
        {
            for (int j = 0; j < m; ++j)
            {
                if (s[i] == t[j])
                {
                    dp[i + 1][j + 1] = max(dp[i + 1][j + 1], dp[i][j] + 1);
                }
                else
                {
                    dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
                    dp[i][j + 1] = max(dp[i][j + 1], dp[i][j]);
                    dp[i + 1][j + 1] = max({dp[i + 1][j + 1], dp[i + 1][j], dp[i][j + 1]});
                }
            }
        }

        cout << dp[n][m] << endl;
    }
    return 0;
}

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

int dp[1000+1][1000+1];

int main() {
    int n; 
    cin >> n;
    while(n--) {
        string s, t; cin >> s >> t;
        int N = s.length();
        int M = t.length();
        dp[0][0] = 0;
        for(int i = 0; i < N; i++) {
            for(int j = 0; j < M; j++) {
                if(s[i] == t[j]) dp[i + 1][j + 1] = dp[i][j] + 1;
                else dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
            }
        }
        cout << dp[N][M] << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <cstring>
#include <algorithm>
#include <climits>
#include <string>
#include <vector>

using namespace std;
int q;
string text;
int ans[160];
int dp[1100][1100];

int main(){
    cin >> q;
    vector<string> texts;

    for(int i=0;i<q*2;i++){
         cin >> text;
         texts.push_back(text);
    }
    for(int k=0;k<q;k++){
        memset(dp, 0, sizeof(dp));
        for(int i=0;i<texts[2*k].size();i++){
            for(int j=0;j<texts[2*k+1].size();j++){
                if(texts[2*k][i]==texts[2*k+1][j]) dp[i+1][j+1] = max(dp[i][j]+1, max(dp[i+1][j], dp[i][j+1]));
                else dp[i+1][j+1] = max(dp[i+1][j], dp[i][j+1]);
            }
        }
        ans[k]=dp[texts[2*k].size()][texts[2*k+1].size()];
    } 
    for(int i=0;i<q;i++)cout << ans[i] << endl;
}

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

int lcs(string, string);

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;
}

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;
}

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

int LCS(string p, string q) {
	vector<vector<int> > f(p.size()+1, vector<int>(q.size()+1,0));
	int t;
	for (int i = 1; i <= p.size(); i++) {
		for (int j = 1; j <= q.size(); j++) {
			if (p[i-1] == q[j-1])
				f[i][j] = f[i - 1][j - 1] + 1;
			else if (f[i][j - 1] > f[i - 1][j])
				f[i][j] = f[i][j - 1];
			else
				f[i][j] = f[i - 1][j];
		}
	}
	return f[p.size()][q.size()];
}

int main() {
	int n;
	string p[150];
	cin >> n;
	for (int i = 0; i < n; i ++) {
		cin >> p[2*i] >> p[2*i + 1];
	}
	for (int i = 0; i < n; i++) {
		cout << LCS(p[2*i], p[2 * i + 1])<<endl;
	}
	return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
    using namespace std;
int lcs(string x,string y){
    int c[1010][1010];
    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(){
    int q;
    string x;
    string y;
    scanf("%d",&q);
    for (int i=0; i<q; i++) {
        cin>>x>>y;
        cout<<lcs(x, y)<<endl;
    }
    return 0;
}

C++: #include<iostream>
#include <cstdlib>
#include<list>
#include<stdio.h>
#include<algorithm>
#include<string>
#include<stack>
#define MAX 1001
using namespace std;
int main() {
	int n; cin >> n;
	string x, y; int data[MAX][MAX] = {0,0};
	for (int d = 0; d <n; d++)
	{
		cin >> x >> y;
		for (int i = 0; i < y.size(); i++)
		{
			for (int j = 0; j < x.size(); j++)
			{
				if (y[i] == x[j]) {
					data[j + 1][i + 1] = data[j][i] + 1;
				}
				else {
					data[j + 1][i + 1] = max(data[j + 1][i], data[j][i + 1]);
				}
			}
		}
		cout << data[x.size()][y.size()]<<endl;
	}
	
	return 0;
}