Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	Q := sc.nextInt()
	for q := 0; q < Q; q++ {
		X, Y := sc.nextStr(), sc.nextStr()
		xLen, yLen := len(X), len(Y)
		dp := make([][]int, xLen+1)
		for i := 0; i <= xLen; i++ {
			dp[i] = make([]int, yLen+1)
		}
		for x := 0; x <= xLen; x++ {
			for y := 0; y <= yLen; y++ {
				if x == 0 || y == 0 {
					dp[x][y] = 0
				} else if X[x-1] == Y[y-1] {
					dp[x][y] = dp[x-1][y-1] + 1
				} else {
					dp[x][y] = max(dp[x-1][y], dp[x][y-1])
				}
			}
		}
		fmt.Fprintln(wtr, dp[xLen][yLen])
	}

	wtr.Flush()
}

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

using namespace std;

int main(){
  string X,Y;
  int n;
  cin>>n;
  int ans[n];
  int l=0;

  for(int i=0;i<n;i++){
    ans[i]=0;
  }

  for(int m=0;m<n;m++){
  cin>>X>>Y;
 int N[X.size()+1][Y.size()+1];

  for(int i=0;i<=X.size();i++){
    for(int j=0;j<=Y.size();j++){

      N[i][j]=0;
}
  }

  /*
  for(int i=0;i<X.size();i++){
    cout<<X[i]<<endl;
  }

for(int i=0;i<Y.size();i++){
    cout<<Y[i];
  }
  */

  /* 
for(int i=0;i<=X.size();i++){
  N[i][0]=0;
  }

for(int i=0;i<=Y.size();i++){
  N[0][i]=0;
  }
  */

 int point;

  for(int i=1;i<=X.size();i++){
    for(int j=1;j<=Y.size();j++){
      if(X[i-1]==Y[j-1]){
	point=1;
	
      }else{
	point=0;
      }
       N[i][j]=max({N[i-1][j],N[i][j-1],N[i-1][j-1]+point});
       point=0;
}
   
  }
  ans[l]=N[X.size()][Y.size()];
  l++;
  // cout<<N[X.size()][Y.size()]<<endl;
  /*
  //answer
  for(int i=0;i<=X.size();i++){
    for(int j=0;j<=Y.size();j++){

      cout<<N[i][j]<<" ";
      if(j==Y.size()){
	cout<<endl;
      }
}
  }
  */

  }
  cout<<ans[0]<<endl;
 cout<<ans[1]<<endl;
 cout<<ans[2]<<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;
  c[0][0] = 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]);
    }
  }javascript:void(0)

  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;

int lcs(string str1, string str2)
{
	int len[1001][1001] = { 0 };

	int len1 = str1.length();
	int len2 = str2.length();
	//str1 = ' ' + str1;
	//str2 = ' ' + str2;

	for (int i = 0; i <= len1; i++)
		for (int j = 0; j <= len2; j++) len[i][j] = 0;

	for (int i = 1; i <= len1; i++)
	{
		for (int j = 1; j <= len2; j++)
		{
			if (str1[i] == str2[j]) len[i][j] = len[i - 1][j - 1] + 1;
			else len[i][j] = max(len[i - 1][j], len[i][j - 1]);
		}
	}
	return len[len1][len2];
}

int main()
{
	int n;
	string str1, str2;

	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> str1 >> str2;
		cout << lcs(str1, str2) << endl;
	}

	return 0;
}

C++: #include <iostream>
using namespace std;
const int MAX=1001;
int lcs(string X,string Y) 
{
	int i=0,j=0,c[MAX][MAX],x=X.length(),y=Y.length();
	for(i=0;i<=x;i++)c[i][0]=0;
	for(i=0;i<=y;i++)c[0][i]=0;
	for(i=1;i<=x;i++) 
	for(j=1;j<=y;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 if(c[i-1][j]<c[i][j-1])c[i][j]=c[i][j-1]; 
	else c[i][j]=c[i][j-1];
	return c[x][y];
}
int main()
{
	int n;cin>>n;
	string X,Y;
	while(n--)
	{
		cin>>X>>Y;
		cout<<lcs(X,Y)<<endl;
	}
}

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

int main(){
  int q;
  cin >> q;
  for(int m=0; m<q; m++){
    string wordx, wordy;
    cin >> wordx >> wordy;
    int L[1000][1000]={0};
    
    for(int j=0; j<wordy.size(); j++){
      for(int i=0; i<wordx.size(); i++){
	if(wordx[i]==wordy[j]){
	  L[i+1][j+1] = 1+L[i][j];
	}
	else{
	  L[i+1][j+1] = max(L[i+1][j], L[i][j+1]);
	}
      }
    }
    cout << L[wordx.size()][wordy.size()] << endl;
    
    
  }
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define all(a)  (a).begin(),(a).end()
#define pb push_back
#define INF 99999999

#define MAX_S 200
#define MAX_T 200

template<typename T> int lcs(T s,T t){
    int lens=s.size();
    int lent=t.size();
    int dp[MAX_S+1][MAX_T+1]={};

    rep(i,lens){
        rep(j,lent){
            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]);
        }
    }
    return dp[lens][lent];
}

int main(){
    int n;
    cin>>n;
    rep(i,n){
        string s,t;
        cin>>s>>t;
        cout<<lcs(s,t)<<endl;
    }
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxx = 1010;
int c[maxx][maxx];

int lcs(char s1[],char s2[]) {
	int m = strlen(s1), n = strlen(s2);
	for (int i = 1; i <= m; i++)
		c[i][0] = 0;
	for (int i = 1; i <= n; i++)
		c[0][i] = 0;

	for (int i = 0; i < m; i++) {
		for (int j = 0; j < n; j++) {
			if (s1[i] == s2[j])
				c[i+1][j+1] = c[i][j] + 1;
			else
				c[i+1][j+1] = max(c[i][j+1], c[i + 1][j]);
		}
	}
	return c[m][n];
}
int main()
{
	char s1[maxx], s2[maxx];
	int t;
	scanf("%d", &t);
	for (int i = 0; i < t; i++) {
		scanf("%s %s", s1, s2);
		printf("%d\n",lcs(s1,s2));
	}

	return 0;
}

C++: #include<iostream>
#include<array>
#define REP(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
const int MAX_V = 1001;
array<array<int, MAX_V>,MAX_V> ary;
string strx,stry;
int minimum(int x,int y){
  int res=strx[x]==stry[y]?ary[x-1][y-1]+1:ary[x-1][y-1];
  if(res<ary[x][y-1]) res=ary[x][y-1];
  if(res<ary[x-1][y]) res=ary[x-1][y];
  return res;
}

int main(){
  int n; cin>>n;
  REP(i,n){
    cin>>strx>>stry;
    int sizex=strx.size(),sizey=stry.size();
    REP(j,sizex)
      REP(k,sizey)
        ary[j+1][k+1]=minimum(j+1,k+1);
    cout<<ary[strx.size()][stry.size()]<<endl;
  }
}