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 INF 1e9
#define all(v) v.begin(), v.end()
#define rep(i, n) for(int i = 0; i < n; i++)
#define pb push_back
#define eb emplace_back
#define mp make_pair
using namespace std;

int main(){
    int dp[1001][1001];
    string x, y;
    int q, n, xl, yl, ans;
    cin>>q;
    for(int k = 0; k < q; k++){
        cin>>x>>y;
        for(int i = 0; i <= 1000; i++){
            for(int j = 0; j <= 1000; j++){
	            dp[i][j]=0;
            }
            xl = x.size();
            yl = y.size();
            ans = 0;
        }
        for(int i = 1; i <= xl; i++){
            for(int j = 1; j <= yl; j++){
	            if(x[i-1] == y[j-1]){
	                dp[i][j] = dp[i-1][j-1]+1;
            	}else{
            	    dp[i][j]=max(dp[i-1][j], dp[i][j-1]);
            	}
            }
        }
    cout<<dp[xl][yl]<<endl;
    }
  return 0;
}

C++: #include<iostream>

using namespace std;

int dp[1001][1001];

int main(){
    int q, m, n;
    cin >> q;

    while(q-- > 0){
        string x, y;
        cin >> x >> y;
        x = ' ' + x;
        y = ' ' + y;
        m = x.length();
        n = y.length();
        for(int i = 1; i <= m; i++) dp[i][0];
        for(int i = 1; i <= n; i++) dp[0][i];

        int res = 0;
        for(int i = 1; i <= m; i++){
            for(int j = 1; j <= n; j++){
                if(x[i] == y[j])    dp[i][j] = dp[i-1][j-1]+1;
                else                dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            }
        }

        cout << dp[m][n]-1 << endl;
    }

    return 0;
}

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

using namespace std;

const int maxn=1010;
int c[maxn][maxn];
string s1,s2;

int lcs(int x,int y)
{
	for(int i=1;i<=x;i++)c[i][0]=0;
	for(int j=1;j<=y;j++)c[0][j]=0;
	s1=' '+s1;
	s2=' '+s2;//插入空格
	int maxl=0; 
	for(int i=1;i<=x;++i){
		for(int j=1;j<=y;++j){
			if(s1[i]==s2[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]);//每次取最大值并更新 
		}
	}
	return maxl;
}

int main()
{
	int t;
	cin>>t;
	while(t--){
		memset(c,0,sizeof(c));
		cin>>s1>>s2;
		int len1=s1.length();
		int len2=s2.length();
		int ans=lcs(len1,len2);
		cout<<ans<<endl;
	}
	return 0;	
}

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

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;

void chmax(int &a, int b) {
  if (a < b) a = b;
}

int main() {

  int q;
  cin >> q;
  while (q--) {
    string s, t;
    cin >> s >> t;
    int n = s.size(), m = t.size();
    vector<vector<int>> dp(n + 1, vector<int>(m + 1, 0));
    rep(i, n) rep(j, m) {
      chmax(dp[i + 1][j + 1], dp[i + 1][j]);
      chmax(dp[i + 1][j + 1], dp[i][j + 1]);
      if (s[i] == t[j]) { chmax(dp[i + 1][j + 1], dp[i][j] + 1); }
    }
    cout << dp[n][m] << endl;
  }

  return 0;
}

C++: #include<iostream>
#include<string>
int main()
{
  int n;
  int an[1000];
  int l=0;
  std::cin>>n;
  std::string x;
  std::string y;
  int ans[1000][1000];
  int j,k;
  for(int i=0;i<n;i++){
    std::cin>>x;
    std::cin>>y;
    for(int j=0;j<1000;j++){
      for(int k=0;k<1000;k++){
	ans[j][k]=0;
      }
    }
    for(int j=0;j<x.size();j++){
      for(int k=0;k<y.size();k++){
	if(x[j]==y[k]){
	  ans[j][k]=ans[j-1][k-1]+1;
	}else{
	  if(ans[j][k-1]>ans[j-1][k]){
	    ans[j][k]=ans[j][k-1];
	  }else{
	    ans[j][k]=ans[j-1][k];
	  }
	}
      }
    }
    std::cout<<ans[x.size()-1][y.size()-1]<<'\n';  
  }
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int solve(char* x,char* y){
    int n=strlen(x),m=strlen(y);
    vector<vector<int>> dp(n+1,vector<int>(m+1));
    for(int i=0;i<n+1;i++){
        if(!i)continue;
        for(int j=0;j<m+1;j++){
            if(!j)continue;
            if(x[i-1]==y[j-1])dp[i][j]=dp[i-1][j-1]+1;
            else dp[i][j]=max(dp[i][j-1],dp[i-1][j]);
        }
    }
    return dp[n][m];
}
int main(){
    int q;scanf("%d",&q);
    while(q--){
        char x[1000],y[1000];
        scanf("%s%s",x,y);
        printf("%d\n",solve(x,y));
    }
    return 0;
}

C++: #include <bits/stdc++.h>
#define PB push_back
#define MP make_pair
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define ALL(a) (a).begin(),(a).end()
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
const int INF=1e9;
int dp[1001][1001];
int main(){
      string s,t;
      int n;
      cin>>n;
      while(n--){
            cin>>s>>t;
            memset(dp,0,sizeof(dp));
            REP(i,s.size()){
                  REP(j,t.size()){
                        if(s[i]==t[j])dp[i+1][j+1]=max(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[s.size()][t.size()]<<endl;
      }
}