Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	for i := 0; i < n; i++ {
		x := getNextString(scanner)
		y := getNextString(scanner)

		fmt.Fprintln(writer, lcs(x, y))
	}

	writer.Flush()
}

func lcs(x, y string) int {
	lx := len(x)
	ly := len(y)
	dp := make([][]int, lx+1)
	for i := 0; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
	}
	for i := 0; i < lx; i++ {
		for ii := 0; ii < ly; ii++ {
			if x[i] == y[ii] {
				dp[i+1][ii+1] = dp[i][ii] + 1
				continue
			}
			dp[i+1][ii+1] = dp[i][ii+1]
			if dp[i+1][ii] > dp[i+1][ii+1] {
				dp[i+1][ii+1] = dp[i+1][ii]
			}
		}
	}
	return dp[lx][ly]
}

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;
	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 x, y;
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x >> y;

		cout << lcs(x, y) << endl;
	}
	return 0;
	
}

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

#define LOOP(val,times) for(val = 0;val < (times);++val)


int lcs(string X, string Y){
    int dp[1010][1010];
    int i,j;
    LOOP(i,1010){
        dp[0][i] = 0;
        dp[i][0] = 0;
    }
    LOOP(i,Y.size()){
        LOOP(j,X.size()){
            if(X[j] == Y[i]){
                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[Y.size()][X.size()];    
}

int main(){
    int i,q;
    cin >> q;
    LOOP(i,q){
        string X,Y;
        cin >> X >> Y;
        cout << lcs(X,Y) << endl;
    }
    int k;cin >> k;
}

C++: #include <iostream>
#include <cassert>
#include <cstdlib>
#include <vector>
#include <string>
#include <algorithm>

using namespace std;

int main() {
  int q;
  cin >> q;
  string s, t;
  int ls, lt;
  for (int p=0; p<q; ++p){
    cin >> s >> t;
    ls = s.length();
    lt = t.length();
    int dp[ls+1][lt+1];
    for(int i=0; i<=ls; ++i){
      for(int j=0; j<=lt; ++j){
        if(i == 0 || j == 0){
          dp[i][j] = 0;
        }
        else {
          dp[i][j] = (s[i-1] == t[j-1]) ? max(max(dp[i-1][j-1] + 1, dp[i-1][j]), dp[i][j-1]) : max(dp[i-1][j], dp[i][j-1]);
        }
      }
    }
    cout << dp[ls][lt] << endl;
  }
}

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

#define MAX_N 1000
#define MAX_M 1000

int n;
string s, t;

int dp[MAX_N + 1][MAX_M + 1];

void solve(){
	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 + 1][j + 1] = dp[i][j] + 1;
				} else {
					dp[i + 1][j + 1] = max(dp[i][j], dp[i + 1][j]);
				}
			}
		}
		cout << dp[s.size()][t.size()] << endl;
}

int main(){
	cin >> n;
	for(int i = 0; i < n; i++){
		cin >> s >> t;
		solve();
	}
}

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

string X, Y;
int v[1001][1001];

int  dp(string X, string Y) {
	int n = X.size();
	int m = Y.size();
	memset(v, 0, sizeof(v));
	for (int i = 0; i <= n; i++) {
		v[i][0] = 0;											///０のテーブル
		for (int j = 0; j <= m; j++) {
			v[0][j] = 0;
		}
	}

	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			if (X[i-1] == Y[j-1]) {
				v[i][j] = v[i - 1][j - 1] + 1;
			}
			else {
				v[i][j] = max(v[i - 1][j], v[i][j - 1]);
			}
		}
	}
	return v[n][m];
}

int main(void)
{
	int x;
	cin >> x;
	
	for (int i = 0; i < x; i++) {
		cin >> X >> Y;
		int ans = dp(X, Y);
		cout << ans << endl;
	}
	
	system("pause");
}

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

using namespace std;                                         
                                                             
//L[i][j] X[0]..X[i]??¨X[0]..Y[j]???LCS                        
int L[1000][1000]={};                                        
int main(){
  int testnum;
  cin>>testnum;                                              
  for(int t=0;t<testnum;++t){                                
    string X,Y;                                              
    cin>>X>>Y;
    
    for(int i=0;i<X.length();++i){                           
      for(int j=0;j<Y.length();++j){                         
        if(X[i]==Y[j])
          L[i][j] = 1 + L[i-1][j-1];                         
        else
          L[i][j] = max(L[i][j-1],L[i-1][j]);
      }
    }

    cout << L[X.length()-1][Y.length()-1] << 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 res = 0;

    x = ' ' + x;
    y = ' ' + y;

    for (int i = 0; i <= m; i++) c[i][0] = 0;
    for (int i = 0; i <= n; i++) c[0][i] = 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][j - 1], c[i - 1][j]);
            }
            res = max(res, c[i][j]);
        }
    }

    return res;
}

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 <vector>
#include <algorithm>
#include <string>
#include <map>
#include <queue>
#include <numeric>
#include <climits>
using namespace std;
using ll = long long;
const ll mod = 1000000007;
int n, m;
string s, t;
const int n_max = 1000;
const int m_max = 1000;

int main() {
	cin >> n;
	for(int k=0; k<n; ++k){
        cin >> s >> t;
        int dp[n_max+1][m_max+1] = {0};
	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 + 1][j], dp[i][j + 1]);
			}
		}
	}
        cout << dp[s.size()][t.size()] << endl;
    }
	

	return 0;
}

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

#define MAX 1000

int dp[MAX+1][MAX+1];

int lcs(char x[], char y[]){
  for(int i = 0; i<=strlen(x); i++){
    dp[i][0] == 0;
    dp[0][i] == 0;
  }

  for(int i = 1; i<=strlen(x); i++){
    for(int j = 1; j<=strlen(y); j++){
      dp[i][j] = (x[i] == y[j]) ? dp[i-1][j-1] + 1 :
                                  max(dp[i-1][j],dp[i][j-1]);
    }
  }

  return dp[strlen(x)][strlen(y)];
}

int main(){

  int q;
  scanf("%d", &q);

  char X[MAX + 1];
  char Y[MAX + 1];
  for(int i=0; i<q; i++){
    scanf("%s\n%s\n", X, Y);
    printf("%d\n", lcs(X, Y));
  }

  return 0;
}