Go: package main

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

//Util
func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

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

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

func absInt(a int) int {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func absFloat64(a float64) float64 {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func minFloat64(a, b float64) float64 {
	if a > b {
		return b
	} else {
		return a
	}
}

func str2Int(s string) int {
	n, _ := strconv.Atoi(s)
	return n
}

//Main
var sc = bufio.NewScanner(os.Stdin)
var q int
var X, Y string

func lcs(X, Y string) int {
	lenX := len(X)
	lenY := len(Y)
	dp := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		dp[i] = make([]int, lenY+1)
	}

	res := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if X[i-1] == Y[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
			//fmt.Println(dp)
			res = maxInt(res, dp[i][j])
		}

	}
	return res
}

func main() {
	sc.Split(bufio.ScanWords)
	q = nextInt()

	for i := 0; i < q; i++ {
		X = nextStr()
		Y = nextStr()

		fmt.Println(lcs(X, Y))
	}
}

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

#define REP(i, n) for(int (i) = 0; (i) < (n); (i)++)

string str1, str2;
int dp[1001][1001];
int k;

int solve(int i, int j)
{
  if(dp[i][j] > 0)
    return dp[i][j];
  if(i >= str1.size() || j >= str2.size()){
    if(i < str1.size()){
      return solve(i + 1, k);
    }else{
      return 0;
    }
  }
  if(str1[i] == str2[j]){
    k = j + 1;
    int n, m = 0;
    for(int l = i + 1; l < str1.size(); l++){
      n = solve(l, j + 1);
      m = (n > m) ? n : m;
    }
    dp[i][j] = m + 1;
    return dp[i][j];
  }else{
    return solve(i, j + 1);
  }
}
  
int main()
{
  int q, n, ans = 0;
  cin >> q;
  cin.ignore();
  REP(i, q){
    getline(cin, str1);
    getline(cin, str2);
    if(str1.size() < str2.size())
      swap(str1, str2);
    fill(&dp[0][0], &dp[1001][0], -1);
    REP(j, str1.size()){
      n = solve(j, 0);
      ans = (n > ans) ? n : ans;
    }
    cout << ans << endl;
    ans = 0;
  }
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = (n - 1); i >= 0; i--)
#define ALL(v) v.begin(), v.end()
using namespace std;
using P = pair<int, int>;
typedef long long ll;

void solve() {
  string s, t;
  cin >> s >> t;
  int n = s.size();
  int m = t.size();
  vector<vector<int>> dp(n+1, vector<int>(m+1, 0));
  rep(i, n){
    rep(j, m){
      if(s[i] == t[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] << "\n";
}

int main() {
  int q;
  cin >> q;
  rep(i, q)solve();
  return 0;
}

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

// int c[1000][1000];

int lcs(string x, string y){
  int m = x.size();
  int n = y.size();

  int c[1001][1001];
  for(int i=1;i<=m;i++) c[i][0] = 0;
  for(int j=1;j<=n;j++) c[0][j] = 0;
  x = ' ' + x;
  y = ' ' + y;

  int maxl = 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(){
  int q;
  cin >> q;
  string s1, s2;
  for(int i=0;i<q;i++){
    cin >> s1 >> s2;
    cout << lcs(s1, s2) << endl;
  }
  return 0;
}

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

long int dp[10000][10000];
string  s1, s2;
void solve(){
  for(int i=0;i<=max(s1.size(),s2.size())+1;i++){
     dp[i][i]=0;
  }
  int val;
  for(int x=1;x<=s1.size();x++){
    for(int y=1;y<=s2.size();y++){
	  if(s1[x]==s2[y]){
	    val = max(dp[x-1][y-1]+1,max(dp[x-1][y],dp[x][y-1]));
	  }else{
	    val = max(dp[x-1][y-1],max(dp[x-1][y],dp[x][y-1]));
          }
          dp[x][y] = val;
    }
  }/*
    for(int x=1;x<=s1.size();x++){
    for(int y=1;y<=s2.size();y++){
      cout<<dp[x][y]<<" ";
    }
    cout<<endl;
    }*/
    cout<<dp[s1.size()][s2.size()]<<endl;
}

int main(){ 
  int n;
   cin>>n;
   for(int i=0; i<n; i++){
      cin>>s1>>s2;
      solve();
   }
   return 0;
}

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

using namespace std;

int LCS(string a, string b);
int S[1001][1001];

int main() {
    int n;
    cin >> n;
    string a, b;

    vector<int> ans;
    
    for (int i = 0; i < n; i++) {
        cin >> a;
        cin >> b;
        ans.push_back(LCS(a, b));
    }
    for (int i = 0; i < n; i++) {
        cout << ans[i] << '\n';
    }
}

int LCS(string a, string b) {

    int len_a = a.size();
    int len_b = b.size();
    for (int i = 1; i <= len_a; i++) {
        for (int j = 1; j <= len_b; j++) {
            if (a[i-1] == b[j-1]) S[i][j] = S[i-1][j-1] + 1;
            else {
                S[i][j] = max(S[i][j-1], S[i-1][j]);
            }
        }
    }

    return S[len_a][len_b];
}

C++: #include<iostream>
#include<stdio.h>
//#include <bits/stdc++.h>
#include<vector>
#include<float.h>
#include<iomanip>
#include<algorithm>
#include<string>
#include<cstring>
#include<math.h>
#include<cmath>
#include<sstream>
#include<set>
#include<map>
#include<queue>
#include <cassert>
#include <cmath>
#include<cstdint>

#define INF 1e9
#define rep(i,n)for(int i=0;(i)<(int)(n);i++)
#define REP(i,a,b)for(int i=(int)(a);(i)<=(int)(b);i++)
#define VEC(type, c, n) std::vector<type> c(n);for(auto& i:c)std::cin>>i;
#define vec(type,n) vector<type>(n)
#define vvec(m,n) vector<vector<int>> (int(m),vector<int>(n))
#define ALL(a)  (a).begin(),(a).end()

using namespace std;
using ll = long long;
using Graph = vector<vector<int>>;
using P = pair<int,int>;

vector<int>bitSearch(int bit,int n){
    vector<int>S;
    rep(i,n)if(bit&(1<<i))S.push_back(i);
    return S;
}

int main(){
    int q;
    while(cin>>q){
        rep(i,q){
            string s,t;cin>>s>>t;
            int m = s.size(),n = t.size();
            s.insert(0,"0");
            t.insert(0,"0");
            int dp[m+1][n+1];
            rep(j,m+1)rep(k,n+1)dp[j][k] = 0;
            REP(j,1,m){
                REP(k,1,n){
                    if(s[j] == t[k]){
                        dp[j][k] = max({dp[j][k],dp[j-1][k-1]+1,dp[j-1][k],dp[j][k-1]});
                    }
                    else dp[j][k] = max({dp[j][k],dp[j-1][k],dp[j][k-1]});
                }
            }
            cout<<dp[m][n]<<endl;
        }
    }
}

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

int main(int argc, char const *argv[]) {
        int x; cin>>x;

        while (x--) {
                string s,t; cin>>s>>t;
                int n = s.length(); int m = t.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 (s[i-1]==t[j-1]) dp[i][j] = max(dp[i][j], dp[i-1][j-1]+1);
                                else {
                                        dp[i][j] = max(dp[i][j], max(dp[i-1][j], dp[i][j-1]));
                                }
                        }
                }
                cout << dp[n][m] << endl;
        }

        return 0;
}

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

int main() {
  int q; cin >> q;
  string A, B; cin >> A >> B;
  for (int i=0; i<q; i++) {
    vector<vector<int>> LCS(A.length()+1, vector<int>(B.length()+1,0));
    for (int j=1; j<=A.length(); j++) {
      for (int k=1; k<=B.length(); k++) {
        if(A[j]==B[k]) LCS[j][k]=LCS[j-1][k-1]+1;
        else LCS[j][k] = max(LCS[j-1][k],LCS[j][k-1]);
      }
    }
    cout << LCS[A.length()][B.length()]
  }
}