Go: package main

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

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func bordersInt(in_map [][]int, invalid int) [][]int{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]int, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]int, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func bordersString(in_map [][]string, invalid string) [][]string{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]string, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]string, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func maxInt(args... int) int{
	sort.Ints(args)
	return args[len(args)-1]
}

func main(){
	buf := make([]byte, 0)
    sc.Buffer(buf, 1000000009)
	var n int 
	fmt.Scan(&n)
	dp := make([][]int, 1003)
	for i:=0; i<1003; i++ {
		dp[i] = make([]int, 1003)
	}
	input_lines := scanStringLine(2*n)
	for i:=0; i<n; i++ {
		S, T := input_lines[2*i], input_lines[2*i+1]
		lenS, lenT := len(S), len(T)
		for i:=1; i<lenS+1; i++ {
			for j:=1; j<lenT+1; j++ {
				if S[i-1] == T[j-1] {
					dp[i][j] = dp[i-1][j-1]+1
				} else if S[i-1] != T[j-1] && dp[i-1][j] > dp[i][j-1] {
					dp[i][j] = dp[i-1][j]
				} else {
					dp[i][j] = dp[i][j-1]
				}
				// if S[i-1] == T[j-1] {
				// 	dp[i][j] = maxInt(dp[i-1][j-1]+1, dp[i-1][j], dp[i][j-1])
				// } else {
				// 	dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
				// }
			}
		}
		fmt.Println(dp[lenS][lenT])
	}
}

C++: #include <bits/stdc++.h>
#define ll long long
#define V vector<long long>
#define VV vector<vector<long long>>
#define VVV vector<vector<vector<long long>>>
#define rep(i,n) for(ll (i)=0;(i)<(n);++(i))
using namespace std;

int main() {
    ll q;
    cin>>q;
    rep(i,q){
        string a,b;
        cin>>a>>b;
        VV dp(a.size()+1,V(b.size()+1,0));
        rep(j,a.size()){
            rep(k,b.size()){
                if(a[j]==b[k]){
                    dp[j+1][k+1]=dp[j][k]+1;
                }else{
                    dp[j+1][k+1]=max(dp[j+1][k],max(dp[j][k+1],dp[j][k]));
                }
            }
        }
        cout<<dp[a.size()][b.size()]<<endl;
    }
}

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

int dp[1005][1005];

int lcs(string x, string y){
    for (int i = 1; i <= x.size(); i++){
        for (int j = 1; j <= y.size(); j++)
        {
            if(x[i-1] != y[j-1])
                dp[i][j] = dp[i-1][j] > dp[i][j-1] ? dp[i-1][j] : dp[i][j-1];
            else
                dp[i][j] = dp[i-1][j-1] + 1;
        }
    }
    return dp[x.size()][y.size()];
}

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

C++: #include <iostream>
#include <algorithm>
#include <string>
using namespace std;
const int MAX=1001;
int lcs(string X,string Y) 
{
	int i=0,j=0,c[MAX][MAX],x=X.length(),y=Y.length();
	for(i=0;i<=x;i++)c[i][0]=0;
	for(i=0;i<=y;i++)c[0][i]=0;
	for(i=1;i<=x;i++) 
	for(j=1;j<=y;j++) 
	if(X[i-1]==Y[j-1])c[i][j]=c[i-1][j-1]+1; 
	else c[i][j]=max(c[i][j-1],c[i-1][j]);
	return c[x][y];
}
int main()
{
	int n;cin>>n;
	string X,Y;
	while(n--)
	{
		cin>>X>>Y;
		cout<<lcs(X,Y)<<endl;
	}
}

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

using namespace std;

int solve(string x, string y) {
    int n = x.length();
    int m = y.length();
    vector<vector<int>> dp(n + 1, vector<int>(m + 1, 0));
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            if (x[i - 1] == y[j - 1]) {
                dp[i][j] = dp[i - 1][j - 1] + 1;
            }
           else {
               dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
            }
        }
    }
    return dp[n][m];
}

int main() {
    int n;
    cin >> n;
    string x, y;
    for (int i = 0; i < n; i++) {
        cin >> x >> y;
        cout << solve(x, y) << endl;
    }
    return 0;
}

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

int lcs(string str1, string str2)
{
  int m = str1.size(), n = str2.size();
  int c[1001][1001];
  str1 = ' ' + str1;
  str2 = ' ' + str2;
  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 (str1[i] == str2[j]) c[i][j] = c[i - 1][j - 1] + 1;
      else if (c[i - 1][j] > c[i][j - 1]) c[i][j] = c[i - 1][j];
      else  c[i][j] = c[i][j - 1];
    }
  }
  return (c[m][n]);
}
int main()
{
  int q;
  cin >> q;
  while (q--){
    string str1, str2;
    cin >> str1 >> str2;
    cout << lcs(str1, str2) << endl;
  }
}

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

int max(int a,int b);

int main() {
  int q;
  cin >> q;
  for (int i=0;i<q;++i) {
    string str1,str2;
    cin >> str1 >> str2;
    int size1 = str1.size();
    int size2 = str2.size();
    int matrix[size1+1][size2+1];
    for (int j=0;j<=size1;++j)
      matrix[j][0] = 0;
    for (int j=0;j<=size2;++j)
      matrix[0][j] = 0;
    for (int j=0;j<=size1;++j) {
      for (int k=0;k<=size2;++k) {
	if (j<=0||k<=0) {
	  matrix[j][k] = 0;
	}
	else if (str1[j]==str2[k]) {
	  matrix[j][k] = 1 + matrix[j-1][k-1];
	}
	else {
	  matrix[j][k] = max(matrix[j][k-1],matrix[j-1][k]);
	}
      }
    }
    cout << matrix[size1][size2] << endl;
  }
}

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

C++: #include<iostream>
#include<string>
#include<algorithm>
usig 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++){
    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 inf 1e9
#define ll long long
#define ull unsigned long long
#define M 1000000007
#define P pair<int,int>
#define PLL pair<ll,ll>
#define FOR(i,m,n) for(int i=(int)m;i<(int)n;i++)
#define RFOR(i,m,n) for(int i=(int)m;i>=(int)n;i--)
#define rep(i,n) FOR(i,0,n)
#define rrep(i,n) RFOR(i,n,0)
#define all(a) a.begin(),a.end()
#define IN(n,a) rep(i,n){ cin>>a[i]; }
const int vx[4] = {0,1,0,-1};
const int vy[4] = {1,0,-1,0};
#define PI 3.14159265


void f(){
  string x,y;
  cin>>x>>y;
  int dp[1100][1100]={};
  
  rep(i,x.length()+1){
    rep(j,y.length()+1){
      if(i==0||j==0) continue;
      if(x[i-1]==y[j-1]) dp[i][j]=dp[i-1][j-1]+1;
      else dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
        }
      }
    }
  }

  cout<<dp[(int)x.length()][(int)y.length()]<<endl;
}


int main(){
  int q;
  cin>>q;
  while(q--){
    f();
  }
}