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>

using namespace std;
int main(int argc, const char * argv[]) {
    int q, i, m, n, sl1, sl2;
    cin >> q;
    vector<string> strlist;
    string str, str1, str2;
    for(i = 0;i < q;i++){
        cin >> str;
        strlist.push_back(str);
        cin >> str;
        strlist.push_back(str);
    }
    
    //start
    for(i = 0;i < q*2;i += 2){
        str1 = strlist[i];
        sl1 = str1.length();
        str2 = strlist[i+1];
        sl2 = str2.length();
        int dp[sl1+1][sl2+1];
        for(m = 0;m <= sl2;m++){
            dp[0][m] = 0;
        }
        for(m = 0;m <= sl1;m++){
            dp[m][0] = 0;
        }
        for(m = 1;m <= sl1;m++){
            for(n = 1;n <= sl2;n++){
                dp[m][n] = 0;
            }
        }
        for(m = 1;m <= sl1;m++){
            for(n = 1;n <= sl2;n++){
                if(str1[m-1] == str2[n-1]){
                    dp[m][n] = dp[m-1][n-1] + 1;
                }else{
                    dp[m][n] = max(dp[m-1][n], dp[m][n-1]);
                }
            }
        }
        m = sl1;
        n = sl2;
        printf("%d\n", dp[m][n]);
        
    }
    return 0;
}

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

using namespace std;
#define ML 1000

inline int comp_char(char a,char b) { if(a==b) return 1;else return 0;}


int longest_cmmsubseq(string &xcomp,string &ycomp,vector<vector<int>> &memo){
  int ysize=ycomp.size();
  int xsize=xcomp.size();
  int max=0;
  for(int i=0;i<xsize;i++){
    if(ycomp.at(0)==xcomp.at(i)){
      while(i<xsize){ memo.at(i).at(0)=1; i++;}
      continue;
    }
    else memo.at(i).at(0)=0;
  }
  for(int j=0;j<ysize;j++){
    if(ycomp.at(j)==xcomp.at(0)){
      while(j<ysize){ memo.at(0).at(j)=1; j++;}
      continue;
    }
    else memo.at(0).at(j)=0;
  }

  for(int j=1;j<ysize;j++){
    for(int i=1;i<xsize;i++){
      max=memo.at(i-1).at(j-1)+comp_char(xcomp.at(i),ycomp.at(j));
      if(max<memo.at(i-1).at(j)) max=memo.at(i-1).at(j);
      if(max<memo.at(i).at(j-1)) max=memo.at(i).at(j-1);
      memo.at(i).at(j)=max;
      max=0;
    }
  }
  return memo.at(xsize-1).at(ysize-1);
}

int main(void){

  int size;
  cin>>size;

  vector<vector<int>> memo(ML,vector<int>(ML));
  string xcomp,ycomp;
  for(int i=0;i<size;i++){
    cin>>xcomp>>ycomp;
    cout<<longest_cmmsubseq(xcomp,ycomp,memo)<<endl;
  }
}

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=1;i<=X.length();++i){                          
      for(int j=1;j<=Y.length();++j){                        
        if(X[i-1]==Y[j-1])
          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()][Y.length()] << endl;
  }
 
  return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
static const int N = 1000; // 読み取り専用（書き換え不可)

int lcs(string X, string Y){
    int c[N+1][N+1];
    int m = X.size();
    int n = Y.size();
    int maxv = 0;
    X = ' ' + X; //X[0]に空白を挿入
    Y = ' ' + Y; //Y[0]に空白を挿入
    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]);
            }
         maxv = max(maxv,c[i][j]);   
        } 
    }
    return maxv;
}

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<bits/stdc++.h>
using namespace std;
#define int long long

signed main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n; cin >> n;
  while( n-- ) {
    string s,t; cin >> s >> t;
    int N = max(s.size(),t.size());
    vector< vector<int> > dp(N+1,vector<int>(N+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;
}