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 <bits/stdc++.h>
#define rep(i,a) for(i=0;i<a;i++)
using namespace std;

int main(void){
    int i,j,q;
    string x,y;
    vector<vector<int> > lcs;
    cin >> q;
    while(q--){
        cin >> x >> y;
        int M = x.size();
        int N = y.size();
        lcs.resize(M+1);
        rep(i,M+1){
            lcs[i].resize(N+1);
        }
        rep(i,M){
            rep(j,N){
                if(x[i] == y[j])
                    lcs[i+1][j+1] = lcs[i][j]+1;
                else
                    lcs[i+1][j+1] = max(lcs[i+1][j],lcs[i][j+1]);
            }
        }
        cout << lcs[M][N] << endl;
    }
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int main()
{
    int q,i,j,k,l1,l2,m,n;
    string X,Y;
    cin>>q;
    for(i=0; i<q; i++)
    {
        cin>>X>>Y;
        l1=X.length()+1;
        l2=Y.length()+1;
        int arr[l2][l1];
        for(k=0; k<l1; k++)
        {
            arr[0][k]=0;
        }
        for(k=0; k<l2; k++)
        {
            arr[k][0]=0;
        }
        for(k=1; k<l2; k++)
        {
            for(j=1; j<l1; j++)
            {
                if(Y[k-1]==X[j-1])
                {
                    arr[k][j]=1+arr[k-1][j-1];
                }
                else
                {
                    m=arr[k-1][j];
                    n=arr[k][j-1];
                    arr[k][j]=max(m,n);
                }
            }
        }
        cout<<arr[l2-1][l1-1]<<endl;
    }
}

C++: // 最長共通部分列 問題
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<stack>
#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>

using namespace std;

#define MAX_LEN 1000
// 無効な値の定義
const int INV = -1;

int longestCommonSubstring(string a, string b);

int main(void)
{

    int q, len;
    string first_str, second_str;

    cin >> q;

    for(int i = 0; i < q; i++)
    {
        cin >> first_str;
        cin >> second_str;

        len = longestCommonSubstring(first_str, second_str);
        printf("%d\n", len);
    }



    return 0;
}

// 最長共通部分列を算出する関数
int longestCommonSubstring(string str_a, string str_b)

{
    int dp[MAX_LEN + 1][MAX_LEN + 1];
    int a_len, b_len;

    a_len = str_a.size();
    b_len = str_b.size();

    // 文字列の先頭に空白を挿入する
    str_a = " " + str_a;
    str_b = " " + str_b;

    for(int i = 0; i <= a_len; i++)
    {
        dp[i][0] = 0;
    }

    for(int j = 0; j <= b_len; j++)
    {
        dp[0][j] = 0;
    }

    // 最長共通部分列の算出
    for(int i = 1; i <= a_len; i++)
    {
        for(int j = 1; j <= b_len; j++)
        {
            if( str_a[i] == str_b[j] )
            {
                // 最後の文字が一致している時
                dp[i][j] = dp[i - 1][j - 1] + 1;
            }
            else
            {
                // 最後の文字が一致していない時
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
            }
        }
    }

	return dp[a_len][b_len];
}

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

using namespace std;

void
chmax(int& aa, int bb)
{
  if (aa < bb) {
    aa = bb;
  }
}

int
main()
{
  int   qq;

  cin >> qq;

  
  for (int qi = 0; qi < qq; qi++) {
    string      xx;
    string      yy;
    vector<vector<int> > dp;

    cin >> xx;
    cin >> yy;

//    cout << xx << endl;
//    cout << xx.length() << endl;

    dp.assign(xx.length() + 1, vector<int>(yy.length() + 1, 0));

    for (int xi = 0; xi < xx.length(); ++xi) {
      for (int yi = 0; yi < yy.length(); ++yi) {
        //cout << yi << endl;
        if (xx[xi] == yy[yi]) {
          dp[xi + 1][yi + 1] = dp[xi][yi] + 1;
        }
        chmax(dp[xi + 1][yi + 1], dp[xi][yi + 1]);
        chmax(dp[xi + 1][yi + 1], dp[xi + 1][yi]);
      }
    }
    cout << dp.back().back() << endl;
  }
}

C++: #include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<vector>
#include<stdio.h>
#include<cstring>
#include<math.h>
#include<map>
#include<bitset>
#include<iomanip>
#include<queue>
#include<functional>
#include<stack>
#include<tuple>
#include<cassert>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
using P = pair<int, int>;

int n;
int dp[1001][1001];

int main() {
  cin >> n;
  rep(i, n) {
    string x, y;
    cin >> x >> y;
    dp[0][0] = 0;
    rep(i, y.size()) {
      dp[0][i+1] = 0;
    }
    rep(i, y.size()) {
      dp[i+1][0] = 0;
    }
    rep(i, x.size()) {
      rep(j, y.size()) {
        dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
        if(x[i] == y[j]) {
          dp[i+1][j+1] = dp[i][j] + 1;
        }
      }
    }
    cout << dp[x.size()][y.size()] << endl;
  }


  return 0;
}