Go: package main

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

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

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

func lcs(a, b string) int {
	lenA := len(a)
	lenB := len(b)
	dp := make([][]int, lenA+1)
	for i := range dp {
		dp[i] = make([]int, lenB+1)
	}

	for i := 1; i <= lenA; i++ {
		for j := 1; j <= lenB; j++ {
			if a[i-1] == b[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = max(dp[i][j-1], dp[i-1][j])
			}
		}
	}
	return dp[lenA][lenB]
}

func main() {
	n := scanInt()
	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		a := scanString()
		b := scanString()
		fmt.Fprintln(w, lcs(a, b))
	}
	w.Flush()
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#define FOR(i,b,e) for(int i=b;i<e;i++)
#define REP(i,n) FOR(i,0,n)
using namespace std;

int dp[1001][1001];
string s1, s2;

int lcs(int n1, int n2) {
  if (dp[n1][n2] != -1) return dp[n1][n2];
  
  return dp[n1][n2] = max(lcs(n1 - 1, n2), lcs(n1, n2 - 1));
}

int main() {
	cin.tie(0);
 	ios::sync_with_stdio(false);

  REP(i, 1001) dp[i][0] = 0;
  REP(i, 1001) dp[0][i] = 0;

  int q; cin >> q;
  REP(i, q) {
    cin >> s1;
    cin >> s2;

    cout << lcs(s1.length(), s2.length()) << endl;
  }
}

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

#if __has_include("print.hpp")
  #include "print.hpp"
#endif

#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

typedef long long ll;
typedef pair<int, int> p;

int n, w;
vector<vector<int>> dp(500, vector<int>(10500, -1));
vector<int> vv;
vector<int> wv;

void solve(){
  for (int i = n - 1; i >= 0; i--) {
    for (int j = 0; j < w; j++) {
      if(j < wv[i]){
        dp[i][j] = dp[i+1][j];
      }else{
        dp[i][j] = max(dp[i+1][j], dp[i+1][j-wv[i]] + vv[i]);
      }
    }
  }
}

int main(){
  cin >> n >> w;
  for (int i = 0; i < n; i++)
  {
    int tmp1, tmp2;
    cin >> tmp1 >> tmp2;
    wv.push_back(tmp1);
    vv.push_back(tmp2);
  }

  solve();
  cout << dp[0][w] << endl;
}

C++: 
#include<iostream>
#include<algorithm>
#include<string>
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++) {
			cout << c[i][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 n;
	string x, y;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x >> y;

		cout << lcs(x, y) << endl;
	}

	
}

C++: #include <bits/stdc++.h>

#define MOD 1000000007
#define INF (1<<30)
#define INFL (1<<62)
#define pe(str) return cout<<(str)<<endl,0
#define px(str) cout<<(str)<<endl,exit(0)
#define accu(ac,v) cout<<setprecision(ac)<<v<<endl
#define bpc(a) __builtin_popcount(a)
#define pr(str) cout<<(str)<<endl
#define prpr(str) cout<<str<<endl
#define db(str) cerr<<"debug:"<<(str)<<endl
#define dbdb(str) cerr<<"debugs:"<<str<<endl
#define re(i,n) for(int i=0;i<(n);i++)
#define rre(i,n) for(int i=(n);i>=0;i--)
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b);i>=(a);i--)
#define bw(a,b,c) (((a)<=(b))&&((b)<=(c)))
#define hello cout<<"hello"<<endl
#define spre(a) setprecision(a)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define s3(C,T,F) ((C)?(T):(F))
#define max3(a,b,c) max((a),max((b),(c)))
#define min3(a,b,c) min((a),min((b),(c)))
#define max4(a,b,c,d) max((a),max((b),max((c),(d))))
#define min4(a,b,c,d) min((a),min((b),min((c),(d))))
#define enl cout<<endl
#define declare(t,n) t n;cin>>n

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> pii;
typedef complex<int> point;

template<class InputIterator>
void dump(InputIterator first,InputIterator last,char delim=' '){
	for(InputIterator it=first;it!=last;it++){
		if(it!=first)cout<<delim;
		cout<<*it;
	}
}

ull p(ull x,ull y){
	if(y==0) return 1;
	ull A=p(x,y/2)%MOD;
	return (y&1?((A*A)%MOD*x)%MOD: (A*A)%MOD);
	// return (y&1?((A*A)*x):(A*A));
}

template<class T>
void swp(T &a,T &b){
	T t=a; a=b; b=t;
}

int main(void){
	int dp[1001][1001];
	string a,b;
	int n;
	cin>>n;

	while (n--) {
		cin>>a>>b;
		re(i,a.size()) re(j,b.size()) dp[i][j]=0;
		rep(i,1,a.size()+1) rep(j,1,b.size()+1) dp[i][j]=max3(dp[i-1][j-1]+(a[i-1]==b[j-1]),dp[i-1][j],dp[i][j-1]);
		cout<<dp[a.size()][b.size()]<<endl;
	}
	return 0;
}

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

int main()
{
	int q, t1, t2;
	string s1, s2;
	const int maxS = 10;
	int m[maxS][maxS];

	cin >> q;

	for (int i = 0; i < q; i++) {

		for (int i = 0; i < maxS; i++)
			for (int j = 0; j < maxS; j++)
				m[i][j] = 0;

		cin >> s1 >> s2;

		t1 = s1.size() - 1;
		t2 = s2.size() - 1;

		if (s1[0] == s2[0])
			m[0][0] = 1;

		for (int i = 0; i < t1; i++) {
			int f = 0;
			if (s1[i + 1] == s2[0])
				f = 1;
			m[i + 1][0] = max(m[i][0], f);
		}

		for (int j = 0; j < t2; j++) {
			int f = 0;
			if (s2[j + 1] == s1[0])
				f = 1;
			m[0][j + 1] = max(m[0][j], f);
		}

		for (int i = 0; i < t1; i++) {
			for (int j = 0; j < t2; j++) {
				if (s1[i + 1] == s2[j + 1])
					m[i + 1][j + 1] = m[i][j] + 1;
				else
					m[i + 1][j + 1] = max(m[i][j + 1], m[i + 1][j]);
			}
		}

		cout << m[t1][t2] << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<cstdio>
#include<string>
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;
 
 int c[4001][4001]{};
signed main(){
    int n;
    scanf("%d",&n);
    char a[5000];
char b[5000];
    for(int m=0;m<n;m++){
	scanf("%s%s",a,b);
int d,e;
d=strlen(a);
e=strlen(b);
for(int t=0;t<=d;t++){
    for(int w=0;w<=d;w++)c[t][w]=0;
    }
for(int x=0;x<d;x++){
    for(int y=0;y<e;y++){
	if(a[x]==b[y])c[x+1][y+1]=c[x][y]+1;
	else c[x+1][y+1]=max(c[x][y+1],c[x+1][y]);
	}
    }
    printf("%d\n",c[d][e]);
	}
}

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

int main(){
	int q;
	std::string a, b;
	std::vector< int > dp(1001*1001,0);
	
	std::cin >> q;
	
	for(int i=0;i<q;++i){
		std::cin >> a >> b;
		
		for(int x=1;x<=a.length();++x){
			for(int y=1;y<=b.length();++y){
				if(a[x] == b[y]){
					dp[y * 1001 + x] = dp[(y - 1) * 1001 + (x - 1)] + 1;
				}else{
					dp[y * 1001 + x] = std::max(dp[(y - 1) * 1001 + x], dp[y * 1001 + (x - 1)]);
				}
			}
		}
		std::cout << dp[b.length() * 1001 + a.length()] << std::endl;
	}
	
	return 0;
}