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 lcs(string X, string Y) {
	int c[1000][1000];
	int m = X.length();
	int n = Y.length();
	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 if (c[i - 1][j] >= c[i][j - 1]) {
				c[i][j] = c[i - 1][j];
			}
			else {
				c[i][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<iostream>
#include<string>
using namespace std;

int count(const string& X, int i, const string Y, int j){
    if (i >= X.size() || j >= Y.size()) return 0;
    while (X[i] != Y[j]) {
        j++;
        if (j >= Y.size()) return 0;
    }
    return 1 + count(X, i + 1, Y, j + 1);
}

int solve(const string& X, const string& Y) {
    int max = 0;
    for (int i = 0; i < X.size(); i++) {
        int c = count(X, i, Y, 0);
        if (c > max) max = c;
    }
    return max;
}

int main(){
    int q;
    cin >> q;
    for (int i = 0; i < q; i++) {
        string X, Y;
        cin >> X >> Y;
        cout << solve(X, Y) << 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]);
    }
  }

  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>
#define INF 1000000
using namespace std;

int q;
string x,y;
int _dp[1010][1010];
int result[150];

int dp(int posx,int posy){
	if(_dp[posx][posy]) return _dp[posx][posy];
	if(posx == 0 || posy == 0){
		_dp[posx][posy] == 0;
		return 0;
	}else{
		int max = dp(posx-1,posy);
		if(max < dp(posx,posy-1)) max = dp(posx, posy-1);
		if(x[posx-1] == y[posy-1] && max < dp(posx-1,posy-1)+1)
			max = dp(posx-1,posy-1)+1;
		_dp[posx][posy] = max;
		return max;
	}
}

int main(void){
	cin >> q;
	
	for(int i=0; i<q; i++){
		cin >> x >> y;
		result[i] = dp(x.size() ,y.size());
		std::fill((int*) _dp, (int*) (_dp + 1010), 0);
	}
	
	for(int i=0; i<q; i++) cout << result[i] << endl;
	
	return 0;
}

C++: #include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
int main(){
  char str1[1000],str2[1000];
  int LCS[1000][1000]={0};
  int length1,length2;
  int n;
  scanf("%d",&n);
  for(int s=1;s<=n;s++){
   while(cin>>str1>>str2){
     length1=strlen(str1);
     length2=strlen(str2);
     for(int i=0;i<=length1-1;i++){
       LCS[i][0]=0;
     }
     for(int j=0;j<=length2-1;j++){
       LCS[0][j]=0;
     }
     for(int i=1;i<=length1;i++){
       for(int j=1;j<=length2;j++){
         if(str1[i-1]==str2[j-1]) {
           LCS[i][j]=LCS[i-1][j-1]+1;
         }
         else LCS[i][j]=max(LCS[i-1][j],LCS[i][j-1]);
       }
     }
     printf("%d\n",LCS[length1][length2]);
   }
 }
   return 0;
}

C++: #if 0
???????????????????????????Z???Z[1000][1000]??§???????????£??????????????????????????£??????
#endif


#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

int N,len1,len2;
string X,Y;
int Z[1010][1010];

int main() {
  cin >> N;
  for (int i=0; i<N; i++){
    cin >> X >> Y;
    len1 = X.length();
    len2 = Y.length();
    for (int i=1; i<=len1; i++){
      for (int j=1; j<=len2; j++){
       if (X[i-1] == Y[j-1]){
         Z[i][j] = Z[i-1][j-1] + 1;
       }
       else if (Z[i][j-1] > Z[i-1][j]){
         Z[i][j] = Z[i][j-1];
       }
       else{
         Z[i][j] = Z[i-1][j];
       }
     }
   }
   cout << Z[len1][len2] << endl;
 }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define For(I,A,B) for(int I=(A); I < (B); ++I)
int main()
{
int t;
cin>>t;
while(t--){
int a[1000]={0},b[1000]={0},c[200][200];
int x,y,z,k=0,l,i,j;

 For(i,0,200)
 For(j,0,200)
 c[i][j]=0;


 cin>>x>>y;
 For(i,0,x+1)
 For(j,0,y+1)
 c[i][j]=0;
 For(i,1,x+1) cin>>a[i];
 For(i,1,y+1) cin>>b[i];

 For(i,1,x+1)
 For(j,1,y+1)
 {
     if(a[i]==b[j]) c[i][j]=c[i-1][j-1]+1;
     else  c[i][j]=max(c[i-1][j],c[i][j-1]);
 }
    cout<<c[x][y]<<endl;

}
}
    return 0;
}