Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const N = 1001

func max(x, y int) int {
	if x > y {
		return x
	}
	return y
}

func lcs(x, y string) int {
	var c [N][N]int
	m := len(x)
	n := len(y)
	var maxl int

	x = " " + x
	y = " " + y

	for i := 1; i <= m; i++ {
		for 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
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	q, _ := strconv.Atoi(sc.Text())

	var out bytes.Buffer
	for i := 0; i < q; i++ {
		sc.Scan()
		s1 := sc.Text()
		sc.Scan()
		s2 := sc.Text()
		out.WriteString(fmt.Sprintf("%d\n", lcs(s1, s2)))
	}
	return strings.TrimRight(out.String(), "\n")
}

func main() {
	fmt.Println(answer(os.Stdin))
}

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

int main(){
  int i,j,n,c[1001][1001];
  string x,y;
  cin >> n;
  while(n>0){
    n--;
    cin >> x;
    cin >> y;

    int lenx = x.size();
    int leny = y.size();

    for(i = 1; i < lenx; i++){
      c[i][0] = 0;
    }
    for(j = 1; j < leny; j++){
      c[0][j] = 0;
    }
  
    for(i = 0; i < lenx; i++){
      for(j = 0; j < leny; 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];
	}
      }
    }
    cout << c[lenx-1][leny-1] << endl;
  }
  return 0;
}

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

int S[1001][1001];

void prep(string str1, string str2, int len1, int len2)
{
    int a, b, i;
    S[0][0] = 0;
    for(i = 1; i <= len1; i++){ S[i][0] = 0; }
    for(i = 1; i <= len2; i++){ S[0][i] = 0; }
    for(a = 1; a <= len1; a++){
        for(b = 1; b <= len2; b++){
            if(str1[a - 1] == str2[b - 1]){ S[a][b] = 1; }else{ S[a][b] = 0; }
        }
    }
    return;
}

int main()
{
    int i, a, b, q, len1, len2;
    cin >> q;
    string str1, str2;

    for(i = 0; i < q; i++){
        cin >> str1 >> str2;
        len1 = str1.size();
        len2 = str2.size();
        prep(str1, str2, len1, len2);
        for(a = 1; a <= len1; a++){
            for(b = 1; b <= len2; b++){
                if(S[a][b]){ S[a][b] = S[a - 1][b - 1] + 1; }
                else{ S[a][b] = max(S[a - 1][b], S[a][b - 1]); }
            }
        }
		cout << S[len1][len2] << 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;
    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 <cstdio>
#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int lcs(string X, string Y) {
    int m = X.size();
    int n = Y.size();
    int c[m+1][n+1];
    int maxl = 0;
    X = ' ' + X;    // insert empty to X[0]
    Y = ' ' + Y;    // insert empty to Y[0]
    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]);
            }
        }
    }

    return c[m][n];
}

int main() {
    int n;
    scanf("%d", &n);

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

C++: #include <iostream>
#include <algorithm>
#include<string.h>
using namespace std;
int LCS(char *x,char *y);
char x[1001], y[1001];
int lcs[1001][1001];
int main()
{
	int q,i,j;

	cin >> q;
	for (i = 0; i < q; i++) {
		cin >> x;
		cin >> y;
		cout << LCS(x, y) << endl;
	}
}

int LCS(char *x, char *y)
{
	int i, j;
	int len_x, len_y;
	len_x = strlen(x);
	len_y = strlen(y);
	
	for (i = 0; i < len_x; i++) {
		if (x[i] == y[0]) {
			lcs[i][0] = 1;
		}
		else {
			lcs[i][0] = 0;
		}
	}
	for (i = 0; i < len_y; i++) {
		if (x[0] == y[i]) {
			lcs[0][i] = 1;
		}
		else {
			lcs[0][i] = 0;
		}
	}

	for (i = 0; i < len_x; i++) {
		for (j = 0; j < len_y; j++) {
			if (x[i] == y[j]) {
				lcs[i][j] = lcs[i - 1][j - 1] + 1;
				//printf("lcs[%d][%d]=%d\n", i, j, lcs[i - 1][j - 1] + 1);
			}
			if (x[i] != y[j]) {
				lcs[i][j] = max(lcs[i - 1][j], lcs[i][j - 1]);
				//printf("lcs[%d][%d]=%d\n", i, j, max(lcs[i - 1][j], lcs[i][j - 1]));
			}
		}
	//cout << endl;

	}
	for (i = 0; i < len_x; i++) {
		for (j = 0; j < len_y; j++) {
			//printf("%d ", lcs[i][j]);
		}
		//cout << endl;
	}
	//cout << "len_x=" << len_x << endl << "len_y=" << len_y << endl;
			
	return lcs[i-1][j-1];
}

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

#define FOR( i, m, n )  for( int (i) = (m); (i) < (n); (i)++ )
#define REP( i, n )     FOR( i, 0, n )
#define ALL( a )        (a).begin(), (a).end()             

int main() {
	int n; cin >> n;

	int maxl;
	int	dp[1001][1001] = {};
	string s1, s2;
	REP( i, n ) {
		cin >> s1 >> s2;
		maxl = 0;
		FOR( j, 1, s1.size() + 1 ) {
			FOR( k, 1, s2.size() + 1 ) {
				if( s1[j] == s2[k] ) {
					dp[j][k] = dp[j - 1][k - 1] + 1;
				} else {
					dp[j][k] = max( dp[j - 1][k], dp[j][k - 1] );
				}
				maxl = max( dp[j][k], maxl );
			}
		}

		cout << maxl << endl;
	}
}

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



int lcs(string x, string y){

  int m = x.length();
  int n = y.length();

  int c[m + 1][n + 1];

  for(int i = 0; i <= m; i++){
    c[i][0] = 0;
  }
  for(int i = 1; i <= n; i++){
    c[0][i] = 0;
  }

  for(int i = 1; i <= m; i++){
    for(int j = 1; j <= n; 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{
        c[i][j] = c[i][j - 1];
      }
  //    cout << "c" << i << j << c[i][j] << endl;
    }

  }

  return c[m][n];
}

int main(){

  int q;

  string x, y;

  cin >> q;

  for(int i = 0; i < q; i++){
    cin >> x;
    cin >> y;
    cout << lcs(x, y) << endl;
  }



  return 0;
}

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