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<iostream>
#include<cmath>
#include<algorithm>
#include<cstdio>
#include<string>

//#define MAX 1001

using namespace std;

static const int N = 1001;

int Lcs(string X, string Y) {
	int c[N][N];
	int m = X.size();
	int n = Y.size();
	int len = 0;

	X = ' ' + X;
	Y = ' ' + Y;

	for (int j = 0; j<m; j++) {
		c[j][0] = 0;
	}
	for (int k = 0; k<n; k++) {
		c[0][k] = 0;
	}

	for (int j = 1; j<=m; j++) {
		for (int k = 1; k<=n; k++) {

			if (X[j] == Y[k]) {
				c[j][k] = c[j - 1][k - 1] + 1;
			}
			else if (c[j - 1][k] >= c[j][k - 1]) {
				c[j][k] = c[j - 1][k];
			}
			else {
				c[j][k] = max(c[j-1][k], c[j][k-1]);
				
			}
			len = max(len, c[j][k]);
		}
	}
	return len;
	//cout << lon << endl;
}

int main() {
	int q;//データセットの数
	string Xi, Yi;

	cin >> q;
	for (int i = 0;i < q; i++) {
		cin >> Xi >> Yi;

		cout << Lcs(Xi, Yi) << endl;
	}


	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define FOR(I,A,B) for(ll I = (A); I < (B); ++I)
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin()) //xi>=v
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin()) //xi>v
#define NUM(x,v) (POSU(x,v)-POSL(x,v))
const ll INF=1e9+7;
const ll N = 1002;
const ll M = 21;
ll q,dp[N][N];
string x,y;
vector <ll> ans;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin>>q;
	FOR(k,0,q){
		cin>>x>>y;
		FOR(i,0,x.size()+1){
			FOR(j,0,y.size()+1){
				dp[i][j]=0;
			}
		}
		FOR(i,0,x.size()+1){
			FOR(j,0,y.size()+1){
				if(i==0||j==0)dp[i][j]=0;
				else{
					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]);
				} 
			}
		}
		ans.push_back(dp[x.size()][y.size()]);
	}
	FOR(i,0,ans.size()){
		cout<<ans[i]<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
#define MAX 1000
int lcs(string X, string Y) {
	int c[MAX + 1][MAX + 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() {
	int n;
	string a, b;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> a >> b;
		cout << lcs(a, b) << endl;
	}
	return 0;
}

C++: #include<cstdio>
#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
#define N 1000

int lcs(string X,string Y){
  int c[N+1][N+1];
  int m=X.size();
  int n=Y.size();
  int maxcost=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]);
      }
      maxcost=max(maxcost,c[i][j]);
    }
  }
  return maxcost;
}

int main(){
  string s1,s2;
  int n;
  scanf("%d",&n);
  for(int i=0;i<n;i++){
    cin >> s1 >>s2;
    printf("%d\n",lcs(s1,s2));
  }
  return 0;
}

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

int dp[1145][1145];

int main(){
    int n;
    cin>>n;
    while(n--){
        string s,t;
        cin>>s>>t;
        for(int i=0;i<s.size();i++){
            for(int j=0;j<t.size();j++){
                if(s[i]==t[j])dp[i+1][j+1]=dp[i][j]+1;
                else dp[i+1][j+1]=max(dp[i][j+1],dp[i+1][j]);
            }
        }
        cout<<dp[s.size()][t.size()]<<endl;
    }
    return 0;
}

C++: #include<iostream>
#include<map>
#include<deque>
#include<algorithm>
#include<string>
#include<cctype>
using namespace std;
#define REP(i,b,e) for(int i=(int)b;i<(int)e;i++)
#define Rep(i,n) REP(i,0,n)
typedef long long ll;

int q;
string X,Y;

int main(){
    cin>>q;
    Rep(i,q){
        cin>>X>>Y;
        X= ' '+X;
        Y= ' '+Y;
        int m,n;
        int maxl=0;
        m=X.size();
        n=Y.size();
        int c[m+3][n+3];
        Rep(j,m)Rep(k,n) c[j][k]=0;
        REP(j,1,m){
            REP(k,1,n){
                if(X[j]==Y[k]) c[j][k]=c[j-1][k-1]+1;
                else c[j][k]=max(c[j-1][k],c[j][k-1]);
                maxl=max(maxl,c[j][k]);
            }
        }
        cout<<maxl<<endl;
    }
    return 0;
}

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

int main() {
    int q; cin >> q;
    for (int i = 0; i < q; i++) {
        string s, t; cin >> s >> t;
        int n = s.size(), m = t.size();
        int dp[n+1][m+1] = {};
        for (int i= 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                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] << endl;
    }
}

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

int main() {
	int setN;
	cin >> setN;
	string A,B;

	for (int i=0;i<setN;i++) {
		cin >> A;
		cin >> B;
		int L[1000][1000] ={};

		for(int j=1;j<A.length()+1;j++) {
			for(int l=1;l<B.length()+1;l++) {
				if(A[j-1] == B[l-1]) {
					L[j][l] = 1+L[j-1][l-1];

				} else {
					L[j][l] = max(L[j-1][l],L[j][l-1]);
				}
				
			}
		}
		/*
		for(int j=0;j<A.length()+1;j++) {
			cout << endl;
			for(int l=0;l<B.length()+1;l++) {
				cout << L[j][l] << " ";
				
			}
		}
		*/

		cout << L[A.length()][B.length()] << endl;


	}
}