Go: package main

/*
最長共通部分列
*/

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

func larger(l, r int) int {
	if l > r {
		return l
	}
	return r
}

var memo [1001][1001]int

func countLCS(x, y string) int {
	x = " " + x
	y = " " + y
	max := 0
	for xi := 1; xi < len(x); xi++ {
		for yi := 1; yi < len(y); yi++ {
			if x[xi] == y[yi] {
				memo[xi][yi] = memo[xi-1][yi-1] + 1
			} else {
				memo[xi][yi] = larger(memo[xi-1][yi], memo[xi][yi-1])
			}
			max = larger(max, memo[xi][yi])
		}
	}
	return max
}

func main() {
	scanner := makeScanner(1024)
	q := eGetInt(scanner)
	for i := 0; i < q; i++ {
		x := eGetLine(scanner)
		y := eGetLine(scanner)
		fmt.Println(countLCS(x, y))
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}
func min(a []int) int {
	m := a[0]
	for _, v := range a {
		if v < m {
			m = v
		}
	}
	return m
}

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

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

int main() {
    int q;
    cin >> q;
    for(int i=0; i<q; i++) {
        string A,B;
        cin >> A >> B;
        int aSize = A.size();
        int bSize = B.size();
        int c[aSize+1][bSize+1];
        for(int i=0; i<=aSize; i++) c[i][0] = 0;
        for(int j=0; j<=bSize; j++) c[0][j] = 0;
        for(int i=1; i<=aSize; i++) {
            for(int j=1; j<=bSize; j++) {
                if(A[i-1] == B[j-1]) c[i][j] = c[i-1][j-1] + 1;
                else c[i][j] = max(c[i-1][j], c[i][j-1]);
            }
        }
        cout << c[aSize][bSize] << endl;
    }
}

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();

  for (int i = 0; i < m; i++) {
    for (int j = 0; j < n; j++) {
      if (X[i] == Y[j]) {
        if (i == 0 || j == 0) 
          c[i][j] = 1;
        else 
          c[i][j] = c[i - 1][j - 1] + 1;
      }
      else {
        if (i == 0 || j == 0) 
          c[i][j] = 0;
        else 
          c[i][j] = max(c[i][j - 1], c[i - 1][j]);
      }
    }
  }
  return c[m - 1][n - 1];
}

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 <algorithm>
#include <cstring>
using namespace std;
const int MAX = 1001;

int main(){
  int dp[MAX][MAX];
  int t;

  cin >> t;
  while(t--){
    string a,b;

    memset(dp,0,sizeof(dp));

    cin >> a >> b;
    for(int i = 0 ; i < (int)a.size() ; i++){
      for(int j = 0 ; j < (int)b.size() ; j++){
	if(a[i] == b[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[a.size()][b.size()] << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <algorithm>
#include <cstring>
#include <vector>
#include <string>
using namespace std;

char str1[1010], str2[1010];
int f[1010][1010];
int main(){
	int q = 0;
	cin >> q;
	while (q--) {
		scanf("%s%s", str1 + 1, str2 + 1);
		int m = strlen(str1+1);
		int n = strlen(str2+1);
		f[0][0] = 0;
		for (int i = 1; i <= m; i++) {
			for (int j = 1; j <= n; j++) {
				if (str1[i] == str2[j]) 
					f[i][j] = f[i-1][j-1]+1;
				else f[i][j] = 0;
				f[i][j] = max(f[i][j],f[i-1][j]);
				f[i][j] = max(f[i][j],f[i][j-1]);

			}
		}
		printf("%d\n", f[m][n]);
		
	
	}
	return 0;
    
}

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

using namespace std;

int lcs (string x, string y) {

    int m, n, c[1001][1001], i, j, maxl = 0;

    m = x.size();
    n = y.size();

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

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

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

                if (x[i - 1] == y[j - 1]) {
                    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, i;
    string x, y;

    cin >> N;

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

    }

    return 0;

}

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

int main(){
  int n;
  char x[1001],y[1001];
  int dp[1002][1002];
  


  //load n;
  cin >>n;
  for(int i=0;i<n;i++){
    //initialize
    for(int i=0;i<1002;i++){
      for(int j=0;j<1002;j++){
	dp[i][j]=0; 
      }
    }
    //load string
    scanf("%s",x);
    scanf("%s",y);
    //dp
    for(int j=0;j<strlen(x);j++){
      for(int k=0;k<strlen(y);k++){
	if(x[j]==y[k]){
	  dp[j+1][k+1]=dp[j][k]+1;
	}

	else{
 
	  if(dp[j][k+1]>dp[j+1][k]){
	    dp[j+1][k+1]=dp[j][k+1];
	  }

	  else{
	    dp[j+1][k+1]=dp[j+1][k];
	  }
	}
      }
    }

    //print
    cout <<dp[strlen(x)][strlen(y)]<<endl;
  }



  return 0;
}

C++: #include <iostream>

using namespace std;

int lcs(string X, string Y) {
  X = ' ' + X;
  Y = ' ' + Y;
  int memo[1010][1010];
  int maxl = 0;

  // 初期化 境界条件を考える必要がなくなる
  for (int i = 0; i < X.size(); i++) memo[i][0] = 0;
  for (int j = 0; j < Y.size(); j++) memo[0][j] = 0;

  for (int i = 1; i < X.size(); i++) {
    for (int j = 1; j < Y.size(); j++) {
      if (X[i] == Y[j]) {
        //cout << "count up!" << endl;
        memo[i][j] = memo[i-1][j-1] + 1;
      } else {
        memo[i][j] = max(memo[i-1][j], memo[i][j-1]);
      }
      maxl = max(maxl, memo[i][j]);
    }
  }
  return maxl;
}

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