Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

type Position struct {
	X int
	Y int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}
	for i := 0; i < n; i++ {
		strX := nextText(sc)
		strY := nextText(sc)
		fmt.Println(calcLcs(strX, strY))
	}
}

func calcLcs(strX, strY string) int {
	return lcs(strX, strY, Position{0, 0}, make(map[Position]int))
}

func lcs(strX string, strY string, position Position, memo map[Position]int) int {
	if position.X >= len(strX) || position.Y >= len(strY) {
		return 0
	}
	if v, ok := memo[position]; ok {
		return v
	}
	if strX[position.X] == strY[position.Y] {
		result := lcs(strX, strY, Position{position.X + 1, position.Y + 1}, memo)
		memo[position] = result + 1
		return memo[position]
	} else {
		result1 := lcs(strX, strY, Position{position.X + 1, position.Y}, memo)
		result2 := lcs(strX, strY, Position{position.X, position.Y + 1}, memo)
		var result int
		if result1 > result2 {
			result = result1
		} else {
			result = result2
		}
		memo[position] = result
		return result
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

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

int main() {
  std::ios::sync_with_stdio(false);
  cout.tie(0);
  cin.tie(0);
  int N;
  cin>>N;
  string S1,S2;
  for (int k=0; k<N; k++) {
    cin>>S1>>S2;
    int m=S1.length();
    int n=S2.length();
    S1=' '+S1;
    S2=' '+S2;
    int lcs[1001][1001];
    for (int i=1; i<=m; i++) {
      lcs[i][0]=0;
    }
    for (int j=1; j<=n; j++) {
      lcs[0][j]=0;
    }
    int maxl=0;
    for (int i=1; i<=m; i++) {
      for (int j=1; j<=n; j++) {
        if (S1[i]==S2[j]) {
          lcs[i][j]=lcs[i-1][j-1]+1;
        }
        else {
          lcs[i][j]=max(lcs[i-1][j],lcs[i][j-1]);
        }
        maxl=max(maxl,lcs[i][j]);
      }
    }
    cout<<maxl<<endl;
  }
  return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
static const int N =1000;

int lcs(string Xtw,string Ytw){
    int c[N+1][N+1];
    int m=Xtw.size();
    int n=Ytw.size();
    int maxl=0;
    Xtw=' '+Xtw;
    Ytw=' '+Ytw;
    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(Xtw[i]==Ytw[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]);
        }
    }   

    return maxl;
}

int main(){
    string s1tw,s2tw;
    int n; cin>>n;
    for(int i=0;i<n;i++){
        cin>>s1tw>>s2tw;
        cout<<lcs(s1tw,s2tw)<<endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include<algorithm>
using namespace std;
int main(void){
    int n;
    cin>>n;
    string x,y;
    for(int i=0;i<n;i++){
        cin>>x>>y;
        int c[x.size()+1][y.size()+1];
        for(int j=0;j<x.size()+1;j++){
            for(int k=0;k<y.size()+1;k++){
                if(j==0||k==0)c[j][k]=0;
                else if(j>0&&k>0&&x[j-1]==y[k-1]) c[j][k]=c[j-1][k-1]+1;
                else if(j>0&&k>0&&x[j-1]!=y[k-1])c[j][k]=max(c[j][k-1],c[j-1][k]);
            }
        }
        int maxi=0;
        for(int j=0;j<x.size()+1;j++){
            for(int k=0;k<y.size()+1;k++){
               maxi=max(maxi,c[j][k]);
               c[j][k]=0;
            }
        }
        cout<<maxi<<endl;
    }
    
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
#define ll long long
#define endl '\n'
using namespace std;
int dy[4] = { 1, 0, -1, 0 }, dx[4] = { 0, 1, 0, -1 };
typedef pair<ll, ll> P;
const int MAX_N = 1000;
int dp[MAX_N + 1][MAX_N + 1];
string x, y;
int q;

int solve(string x, string y)
{
    int n = x.size(), m = y.size();
    memset(dp, 0, sizeof(dp));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (x[i] == y[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]);
            }
        }
    }
    return dp[n][m];
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> q;
    for (int i = 0; i < q; i++) {
        cin >> x >> y;
        cout << solve(x, y) << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<string>
using namespace std;
static const int Max = 1000;
int getlong(string a, string b){
int n,m,i,j,as=0;
	int cs[Max + 1][Max + 1];
	n=a.size();
	m=b.size();

	a=' '+a;
	b=' '+b;
	cs[0][0]=0;
	for(i=1;i<=n;i++)
	cs[i][0]=0;
	for(i=1;i<=m;i++)
	cs[0][i]=0;
	for(i=1;i<=n;i++){
		for(j=1;j<=m;j++){
			if(a[i]==b[j])
			cs[i][j]=cs[i-1][j-1]+1;
			else
			cs[i][j]=max(cs[i][j-1],cs[i-1][j]);
		as=max(as,cs[i][j]);
		}
		
	}
	return as;
}
main(){
	int q,i;
	string a,b;
	cin>>q;
	for(i=0;i<q;i++){
		cin>>a>>b;
		printf("%d\n",getlong(a,b));
	}
	return 0;
}

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

using namespace std;

int main() {
	int n, l1, l2;
	string s1, s2;

	cin >> n;
	while (n--) {
		cin >> s1 >> s2;
		l1 = s1.size();
		l2 = s2.size();

		int dp[l1 + 1][l2 + 1];
		for (int i = 0; i <= l1; i++) {
			for (int j = 0; j <= l2; j++) {
				dp[i][j] = 0;
			}
		}
		for (int i = 1; i <= l1; i++) {
			for (int j = 1; j <= l2; j++) {
				if (s1[i - 1] == s2[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[l1][l2] << endl;
	}

	return 0;
}

C++: #include<bits/stdc++.h>

using namespace std;
int dp[1002][1002];
int main(){
    int T;
    cin>>T;
    while(T--){
        #ifdef LCS
        string s;
        cin>>s;
        int len=s.size();
        int *dp=new int[len+1];
        dp[0]=1;
        int ans=1;
        for(int i=1;i<len;i++){
            char ch=s[i];
            int cnt=0;
            for(int j=0;j<=i-1;j++){
                if(s[j]<ch) cnt=max(cnt,dp[j]);
            }
            dp[i]=cnt+1;
            ans=max(ans,dp[i]);
        }
        cout<<ans<<endl;
        #endif//LCS
        string s1,s2;
        cin>>s1>>s2;
        int len1=s1.size(),len2=s2.size();
        int len=max(len1,len2);
        for(int i=0;i<=len;i++) {
            dp[0][i]=0;
            dp[i][0]=0;
        }
        int ans=0;
        for(int i=0;i<len1;i++){
            for(int j=0;j<len2;j++){
                if(s1[i]==s2[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[len1][len2]<<endl;
    }
}