Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	for i := 0; i < n; i++ {
		x := getNextString(scanner)
		y := getNextString(scanner)

		fmt.Fprintln(writer, lcs(x, y))
	}

	writer.Flush()
}

func lcs(x, y string) int {
	lx := len(x)
	ly := len(y)
	dp := make([][]int, lx+1)
	for i := 0; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
	}
	for i := 0; i < lx; i++ {
		for ii := 0; ii < ly; ii++ {
			if x[i] == y[ii] {
				dp[i+1][ii+1] = dp[i][ii] + 1
				continue
			}
			dp[i+1][ii+1] = dp[i][ii+1]
			if dp[i+1][ii] > dp[i+1][ii+1] {
				dp[i+1][ii+1] = dp[i+1][ii]
			}
		}
	}
	return dp[lx][ly]
}

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

void fnInput(vector<string>& rvsStrX, vector<string>& rvsStrY)
{
  int nMaxSiz;
  cin >> nMaxSiz;
  rvsStrX.resize(nMaxSiz);
  rvsStrY.resize(nMaxSiz);

  for (int i = 0; i < nMaxSiz; ++i)
  {
    cin >> rvsStrX[i] >> rvsStrY[i];
    rvsStrX[i] = ' ' + rvsStrX[i];
    rvsStrY[i] = ' ' + rvsStrY[i];
  }
}

int fnLngCmnSubseq(const vector<string>& cnrvsStrX, const vector<string>& cnrvsStrY)
{
  vector<vector<int>> vvnLcsDP;

  for (int i = 0; i < cnrvsStrX.size(); ++i)
  {
    const int nMAXNX = cnrvsStrX[i].size();
    const int nMAXNY = cnrvsStrY[i].size();
    vvnLcsDP.resize(nMAXNX, vector<int>(nMAXNY, 0));

    for (int nx = 1; nx < nMAXNX; ++nx)
      for (int ny = 1; ny < nMAXNY; ++ny)
        if (cnrvsStrX[i][nx] == cnrvsStrY[i][ny])
          vvnLcsDP[nx][ny] = vvnLcsDP[nx - 1][ny - 1] + 1;
        else
          vvnLcsDP[nx][ny] = max(vvnLcsDP[nx - 1][ny], vvnLcsDP[nx][ny - 1]);

    cout << vvnLcsDP[nMAXNX - 1][nMAXNY - 1] << endl;
  }
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<string> vsStrX, vsStrY;

  fnInput(vsStrX, vsStrY);
  fnLngCmnSubseq(vsStrX, vsStrY);
  return 0;
}

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()+1;j++){
      for(int k=1;k<y.size()+1;k++){
	if(x[j-1]==y[k-1]){
	  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>
#include<algorithm>
using namespace 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 x=X.size();
  int y=Y.size();
  int maxl = 0;
  X=' '+X;
  Y=' '+Y;
  for(int i=0;i<=x;i++) c[i][0]=0;
  for(int j=0;j<=y;j++) c[0][j]=0;
  for(int i=1;i<=x;i++){
    for(int j=1;j<=y;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 <bits/stdc++.h>
using namespace std;

int Max(int &a,int b){return a=max(a,b);}

int LCS(string &a,string &b){
  int n = a.size();
  int m = b.size();
  vector <vector<int> > dp(n+1,vector<int>(m+1));

  for(int i=0;i<n;i++)
    for(int j=0;j<n;j++){
      if(a[i] == b[j]) Max(dp[i+1][j+1],dp[i][j]+1);
      Max(dp[i+1][j],dp[i][j]);
      Max(dp[i][j+1],dp[i][j]);
    }
  return dp[n][m];
}

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

C++: #include <stdio.h>

int score[1010][1010];

int max2 (int a, int b){
  if (a >= b) return a;
  else return b;
}

int len_of_str(const char s[]){
  int num = 0;

  while(s[num]) num++;

  return num;
}


int main() {
  char a[1010];
  char b[1010];
  int datanum;
  scanf("%d",&datanum);
  for(int c = 0; c < datanum; c++){

  scanf("%999s",a);
  scanf("%999s",b);
  int num1 = len_of_str(a);
  int num2 = len_of_str(b);


  for(int i = num1; i > 0; i--) a[i] = a[i - 1];
  a[0] = ' ';
  for(int j = num2; j > 0; j--) b[j] = b[j - 1];
  b[0] = ' ';

  for(int i = 0; i <= num1; i++) score[i][0] = 0;
  for(int j = 0; j <= num2; j++) score[0][j] = 0;

  int maximum = 0;

  for(int i = 1; i<= num1; i++){
    for (int j = 1; j <= num2; j++){
      if (a[i] == b[j])score[i][j] = score[i-1][j-1] + 1;
      else max2(score[i][j-1],score[i-1][j]);
      maximum = max2(maximum,score[i][j]);
    }
  }

  printf("%d\n",maximum)
}
  return 0;
}

C++: #include<iostream>
#include<vector>
#include<string>
#include<cmath>
#include<algorithm>
int main(){
  int q;
  std::cin>>q;
  std::vector<std::string> str1,str2;
  std::string str;
  for(int i=0;i<q;i++){
    std::cin>>str;
    str1.push_back(str);
    std::cin>>str;
    str2.push_back(str);
    //std::cout<<str1[i][0]<<"\n";
    //std::cout<<str2[i][0]<<"\n";
  }
  
 
  for (int i = 0; i < q; i++) {
	  int ans[str1[i].length()+1][str2[i].length()+1];
	  for (int j = 0; j < str1[i].length() + 1; j++) {
		  for (int k = 0; k < str2[i].length() + 1; k++) {
			  
			  if (j == 0 || k == 0) {
				  ans[j][k] = 0;
			  }else {
				  //std::cout << " str1= " << str1[i][j-1] << " str2= " << str2[i][k-1] << " \n ";
				  if (str1[i][j-1] == str2[i][k-1]){
					  //std::cout << "ppp";
					  ans[j][k] = std::max({ ans[j - 1][k - 1] + 1,ans[j - 1][k],ans[j][k - 1] });
					  //ans[j][k] = std::max({ 1,2,3 });
				  }else {
					  ans[j][k] = std::max(ans[j - 1][k], ans[j][k - 1]);
				  }
			  }
			  //std::cout << ans[j][k] << " ";
			  
		  }
		  //std::cout << "\n";
	  }
	  std::cout << ans[str1[i].length()][str2[i].length()] << "\n";
  }
  

  return 0;
}

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

int main() {
  int n, max_val;;
  cin >> n;
  string first;
  string second;
  for (int k = 0; k < n; k++) {
    cin >> first;
    cin >> second;
    int result[first.size()+1][second.size()+1];
    max_val = 0;
    for (int i = 0; i <= first.size(); i++) result[i][0] = 0;
    for (int i = 0; i <= second.size(); i++) result[0][i] = 0;
    for (int i = 1; i <= first.size(); i++) {
      for (int j = 1; j <= second.size(); j++) {
        int col = first.size();
        if (first[i-1] == second[j-1]) {
          result[i][j] = result[i-1][j-1] + 1;
        } else {
          result[i][j] = max(result[i-1][j],
                             result[i][j-1]);
        }
        max_val = max(result[i][j], max_val);
      }
    }
    cout << max_val << endl;
  }
  return 0;
}