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>
using namespace std;
typedef long long ll;
#define MM 1000000000
#define MOD MM+7
#define MAX 301000
#define MAP 110
#define initial_value -1
#define Pair pair<int,int>
#define chmax(a,b) (a<b ? a=b:0)
#define chmin(a,b) (a>b ? a=b:0)
ll INF = 1e18;
int dx[4] = {-1,0,1,0};
int dy[4] = {0,-1,0,1};
//union_find
int par[100];
int depth[100];
ll N;
ll x[20],c[20],v[20];
string s,t;

int lcs(string x, string y){
    int dp[1010][1010];
    int m = s.size();
    int n = t.size();
    int mx = 0;
    x = ' ' + x;
    y = ' ' + y;
    for(int i = 0; i <= m; i++){
        for(int j = 0; j <= n; j++){
            dp[i][j] = 0;
        }
    }
    for(int i = 1; i <= m; i++){
        for(int j = 1; j <= n; j++){
            if(x[i] == y[i]){
                dp[i][j] = dp[i-1][j-1] + 1;
            } else {
                dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            }
            mx = max(mx, dp[i][j]);
        }
    }
    return mx;
}
int main(){
    cin >> N;
    for(int i = 0; i < N; i++){
        cin >> s >> t;
        cout << lcs(s,t) << endl;
    }
}

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

int dp[1010][1010];

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

  cin >> q;

  for(int t = 0;t < q;t++){
    cin >> x;
    cin >> y;

    memset(dp, 0, sizeof(dp));
    
    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-1]+1;
	}
	else if(dp[i-1][j] <= dp[i][j-1]){
	  dp[i][j] = dp[i][j-1];
	}
	else{
	  dp[i][j] = dp[i-1][j];
	}
      }
    }
    cout << dp[x.size()][y.size()] << endl;
  }
  return 0;
}

C++: #include <algorithm>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

using namespace std;

typedef long long ll;

#define MOD 1000000007

int main() {
  int q;
  cin >> q;
  while (q--) {
    string x, y;
    cin >> x >> y;
    int n = x.size(), m = y.size();
    vector<vector<int> > dp(n + 1, vector<int>(m + 1));
    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < m; ++j) {
        if (x[i] == y[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 <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, i, j;

  x = ' ' + x;
  y = ' ' + y;

  for(i=0;i<=m;i++) c[i][0] = 0;
  for(j=1;j<=n;j++)c[0][j] = 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 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<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;
  int A[n];
  for(int i = 0; i < n; i++){
    cin >> s1 >> s2;
    A[i] = lcs(s1, s2);
  }
  for(int i = 0; i < n; i++) cout << A[i] << endl;
  return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
using namespace std;
void input(string &x,string &y){
	cin>>x>>y;
}
int lcs(string x,string y){
	vector<vector<int>> tb(vector<vector<int>>((int)x.size()+1,vector<int>(y.size()+1,0)));
	for(int i=1;i<(int)x.size()+1;i++){
		for(int j=1;j<(int)y.size()+1;j++){
			if(x[i-1]==y[j-1])  tb[i][j]=tb[i-1][j-1]+1;
			else tb[i][j]=max(tb[i-1][j],tb[i][j-1]);
		}
	}
	return tb[(int)x.size()][(int)y.size()];
}
int main(){
	int q;
	cin>>q;
	string x,y;
	for(int i=0;i<q;i++){
		input(x,y);
		cout<<lcs(x,y)<<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];
    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() {
    string s1, s2;
    int n; 
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> s1 >> s2;
        cout << Lcs(s1, s2) << endl;
    }
    // for (int i = 0; i < n; i++) {
    //     cout << Lcs(s1[i], s2[i]) << endl;
    // }

    return 0;
}