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] = 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;
int main(){
	int f[1001][1001];
	string s,s1;
	int t,n,m;
	cin>>t; 
	while (t--){
		  memset(f,0,sizeof(f));
		  cin>>s>>s1; 
		  n=s.length(); m=s1.length();
		  s='0'+s; s1='0'+s1;
		  for (int i=1; i<=n; i++)
		      for (int j=1; j<=m; j++){
		      	  if (s[i]==s1[j]){
		      	     f[i][j]=f[i-1][j-1]+1;	
				  }
				  else{
				  	 f[i][j]=max(f[i][j-1],f[i-1][j]);
				  }
			  }
		  cout<<f[n][m]<<endl;
	}
	return 0;
}

C++: #include <stdio.h>
#include <string.h>

void Ics(char *X, char *Y)
{
   int c[1000][1000];
   int m, n, i, j;

   m = strlen(X);
   n = strlen(Y);

   for ( i = 1; i <= m, i++ ) {
      c[i][0] = 0;
   }
   for ( j = 0; j <= n; j++ ) {
      c[0][j] =0;
   }

   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 if ( c[ i - 1 ][ j ] >= c[ i ][ j - 1 ] ){
            c[ i ][ j ] = c[ i - 1 ][ j ];
         } else {
            c[ i ][ j ] = c[ i ][ j - 1 ];
         }
      }
   }
   printf("%d\n", c[ m ][ n ]);
}
     
int main()
{
   int q, i;
   char X[1000], Y[1000];

   scanf("%d", &q);
   for ( i = 0; i < q; i++ ) {
      scanf("%s%s", X, Y);
      Ics(X, Y);
   }
   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]==y[j])  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;



int lcs(string X,string Y){
	
	int c[720][720];
int m = X.size();
int n = Y.size();
int max1 = 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]);
		}
		max1 = max(max1,c[i][j]);
		}
	} 
	return max1;
}



int main(){
	int q;
	int a[500];
	string s1,s2;
	cin>>q;
	for(int i=0;i<q;i++){
		cin>>s1>>s2;
		a[i] = lcs(s1,s2);
	}
	for(int i=0;i<q;i++){
		cout<<a[i]<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#define lth 1000

using namespace std;

int main()
{
	int n, L[1000][1000], Lmax = 0, *save;
	string Xi[lth], Yi[lth];
	cin >> n;
	save = new int[n];
	for (int k = 0; k < n; k++)
	{
		Lmax = 0;
		string X, Y;
		cin >> X >> Y;
		for (int i = 0; i <= X.length(); i++)
		{
			if (i != 0)
				Xi[i] = X.substr(0, i );
		}
		for (int i = 0; i <= Y.length(); i++)
		{
			if (i != 0)
				Yi[i] = Y.substr(0, i );
		}
		for (int i = 0; i <= X.length(); i++)
			for (int j = 0; j <= Y.length(); j++)
			{
				if (i == 0 || j == 0)
					L[i][j] = 0;
				else if (Xi[i][i - 1] == Yi[j][j - 1])
				{
					L[i][j] = L[i - 1][j - 1] + 1;
				}
				else
				{
					L[i][j] = (L[i][j - 1] > L[i - 1][j]?L[i][j - 1] : L[i - 1][j]);
				}
				if (Lmax < L[i][j]) Lmax = L[i][j];
			}
		save[k] = Lmax;
	}
	for (int i = 0; i < n; i++)
		cout << save[i] << endl;
	//system("pause");
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <map>

using namespace std;
typedef long long lint;

int dp[1111][1111];

void chmax(int& x, const int y) {
    x = max(x, y);
}

int main() {
    int Q;
    cin >> Q;
    for (int q = 0; q < Q; q++) {
        string X, Y;
        cin >> X >> Y;
        const int N = X.size(), M = Y.size();
        for (int i = 0; i <= N; i++) {
            for (int j = 0; j <= M; j++) {
                dp[i][j] = 0;
            }
        }
        for (int i = 1; i <= N; i++) {
            for (int j = 1; j <= M; j++) {
                chmax(dp[i][j], dp[i-1][j]);
                chmax(dp[i][j], dp[i][j-1]);
                if (X[i-1] == Y[j-1]) chmax(dp[i][j], dp[i-1][j-1] + 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;
	X=' '+X;//??¨X[0]????????\?????????
	Y=' '+Y;//??¨Y[0]????????\?????????
	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;
		int ans=lcs(s1,s2);
		if(ans<=20)cout<<ans<<endl;
		else cout<<"20"<<endl;
	}
	return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>

using namespace std;

short dp[1010][1010];

int main(void)
{
    int q;
    cin >> q;
    while (q)
    {
        string X, Y;
        cin >> X >> Y;
        int Xs = X.size(), Ys = Y.size();
        for (int i = 0; i < Xs; i++) dp[i][0] = 0;
        for (int j = 0; j < Ys; j++) dp[0][j] = 0;
        for (int i = 0; i < Xs; i++)
        {
            for (int j = 0; j < Ys; j++)
                dp[i + 1][j + 1] = ((X[i] == Y[j]) ? dp[i][j] + 1 : max(dp[i + 1][j], dp[i][j + 1]));
        }
        cout << dp[Xs][Ys] << endl;
        q--;
    }
    return 0;
}