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<cstdio>
#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
#define N 1000

int lcs(string X,string Y){
  int c[N+1][N+1];
  int m=X.size();
  int n=Y.size();
  int maxcost=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]);
      }
      maxcost=max(maxcost,c[i][j]);
    }
  }
  return maxcost;
}

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

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

constexpr int MAX_XY = 1000;

int lx, ly, q, dp[MAX_XY][MAX_XY];
std::string sx, sy;

void fill_dp(){
    for(int i = 1; i <= lx; ++i){
        for(int j = 1; j <= ly; ++j){
            if(sx[i - 1] == sy[j - 1]) dp[i][j] = dp[i - 1][j - 1] + 1;
            else dp[i][j] = std::max(dp[i - 1][j], dp[i][j - 1]);
        }
    }
}

void solve(){
    fill_dp();
    std::cout << dp[lx][ly] << std::endl;
    return;
}

int main(){
    std::cin >> q;
    
    for(int i = 0; i < q; ++i){
        std::cin >> sx >> sy;
        lx = sx.size(), ly = sy.size();
        solve();
    }
    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
#define len_max 1000


string X;
string Y;
int dp[len_max+1][len_max+1];

int lcs(){
    int m = X.length();
    int n = Y.length();

    X = ' ' + X;//ずらす
    Y = ' ' + Y;
    

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

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

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

}


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

    int ans[q];

    for(int i = 0; i < q; i++){
        cin >> X >> Y;
        //printf("%d\n", lcs());
        ans[i] = lcs();
    }

    for(int i = 0; i < q; i++){
        printf("%d\n", ans[i]);
    }

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
const int MAXL = 1e3+7;
char s1[MAXL];
char s2[MAXL];
int dp[MAXL][MAXL];
int maxLCS(char s1[], char s2[]){
    int l1 = strlen(s1);
    int l2 = strlen(s2);
    int i;
    for(i = 0; i <= l1; i++){
        dp[0][i] = 0;
    }
    for(i = 0; i <= l2; i++){
        dp[i][0] = 0;
    }
    int j;
    for(i = 1; i <= l2; i++){
        for(j = 1; j <= l1; j++){
            int max_k = max(dp[i-1][j], dp[i][j-1]);
            if(s1[j-1] == s2[i-1]) max_k = max(max_k, dp[i-1][j-1]+1);
            else max_k = max(max_k, dp[i-1][j-1]);
            dp[i][j]= max_k;
        }
    }
    return dp[l2][l1];
}
int main(){
//    freopen(".../in.txt", "r", stdin);
    int q;
    scanf("%d", &q);
    for(int i = 0; i < q; i++){
        scanf("%s", s1);
        scanf("%s", s2);
        int q = maxLCS(s1, s2);
        printf("%d\n", q);
    }
    return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <string>
#include <cmath>

#define MAX_LENGTH 1000
#define NIL -1
using namespace std;
//think easy make easy

int q;//num of datasets
string X;
string Y;
char map[MAX_LENGTH+1][MAX_LENGTH+1];

int findMaxLength(int x,int y){//x:Xの終端.y:Yの終端(0オリジン)
	int val;

	if(x < 0 || y < 0) return 0;

	if(map[x][y] == NIL){
		if(X.at(x) == Y.at(y)){
			val = findMaxLength(x-1,y-1) +1;
		}else{
			val = max(findMaxLength(x-1,y),findMaxLength(x,y-1));
		}
		map[x][y] = val;//メモ
		return val;
	}else return map[x][y];
}

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

	for(int i=0;i<q;i++){
		cin >>X; cin >> Y;
		for(int i=0;i<X.size();i++){
			for(int j=0;j<Y.size();j++){
				map[i][j] = NIL;
			}
		}
	
		cout <<findMaxLength(X.size()-1,Y.size()-1) <<endl;
	}

	return 0;
}

C++: #include <algorithm>
#include<iostream>
#include<vector>
#include<list>
#include<map>
#include<set>
#include<string>
#include <sstream>

#include<stdlib.h>
#include<string.h>
#include<math.h>
#include<limits.h>
using lll = long long;
using ull = unsigned long long;
using namespace std;
int dp[1001][1001];
int lcs(string x,string y){
  int m,n;
  lll ii,jj,kk;
  
  m = x.size();
  n = y.size();
  memset(dp,0,sizeof(dp));
  int maxl = 0;

  for(ii=0;ii<m;ii++){
    for(jj=0;jj<n;jj++){
      if(x[ii] == y[jj]){
        dp[ii+1][jj+1] = dp[ii][jj] + 1;
      }
      else{
        dp[ii+1][jj+1] = max(dp[ii][jj+1],dp[ii+1][jj]);
      }

      maxl = max(maxl,dp[ii+1][jj+1]);
      
    }
  }
  return maxl;
}

int main(){
  lll ii,jj,kk;
  vector<int> ret;
  int q;
  string x,y;

  cin >> q;

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

  return 0;
}