Go: package main

import (
	"fmt"
)

func main() {
	var q int
	fmt.Scan(&q)

	for i := 0; i < q; i++ {
		var x, y string
		fmt.Scan(&x)
		fmt.Scan(&y)

		xs := []rune(x)
		ys := []rune(y)

		xn := len(xs)
		yn := len(ys)
		dp := make([][]int, xn+1)
		for j := 0; j <= xn; j++ {
			dp[j] = make([]int, yn+1)
		}

		for j := 1; j <= xn; j++ {
			for k := 1; k <= yn; k++ {
				dp[j][k] = max(dp[j-1][k], dp[j][k-1])
				if xs[j-1] == ys[k-1] {
					dp[j][k] = max(dp[j][k], dp[j-1][k-1] + 1)
				} else {
					dp[j][k] = max(dp[j][k], dp[j-1][k-1])
				}
			}
		}
		fmt.Println(dp[xn][yn])
	}
}

func max(a, b int) int {
	if a < b {
		return b
	} else {
		return a
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define FOR(I,A,B) for(ll I = (A); I < (B); ++I)
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin()) //xi>=v
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin()) //xi>v
#define NUM(x,v) (POSU(x,v)-POSL(x,v))
const ll INF=1e9+7;
const ll N = 1002;
const ll M = 21;
ll q,dp[N][N];
string x,y;
vector <ll> ans;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin>>q;
	FOR(k,0,q){
		cin>>x>>y;
		FOR(i,0,x.size()+1){
			FOR(j,0,y.size()+1){
				dp[i][j]=0;
			}
		}
		FOR(i,0,x.size()+1){
			FOR(j,0,y.size()+1){
				if(i==0||j==0)dp[i][j]=0;
				else{
					if(x[i]==y[j])dp[i][j] = max(dp[i-1][j]+1,dp[i][j-1]+1);
					else dp[i][j] = max(dp[i-1][j],dp[i][j-1]);
				} 
			}
		}
		ans.push_back(dp[x.size()][y.size()]);
	}
	FOR(i,0,ans.size()){
		cout<<ans[i]<<endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define INF 10000
using namespace std;

int main(){
  int N; cin>>N;
  for (int i =0; i<N; i++) {
    string s1,s2; cin >> s1 >> s2;
    int s1N = s1.size();
    int s2N = s2.size();
    int dp[s1N+1][s2N+1];
    
    for(int j=0; j<=s1N; j++) dp[j][0] =0;
    for(int k=0; k<=s2N; k++) dp[0][k] =0;
  
    for(int j=1; j<=s1N; j++){
      for(int k=1; k<=s2N; k++){ 
        if(s1[j-1] == s2[k-1]) {
          dp[j][k] = dp[j-1][k-1] +1;
        } else {
          dp[j][k] = max(dp[j][k-1], dp[j-1][k]);
        }
      }
    }
    cout << dp[s1N][s2N] <<endl; 
  }
}

C++: #include <iostream>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <string>
#include <cctype>
#include <stack>
#include <queue>
#include <vector>
#include <cstdlib>
#include <list>
#define _USE_MATH_DEFINES
#include <math.h>

using namespace std;

int lcs(string X, string Y) {
	int n, m;
	int c[1001][1001] = { 0 };
	int maxlcs = 0;;

	m = X.size();
	n = Y.size();


	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][j - 1],c[i - 1][j]);

			maxlcs = max(maxlcs, c[i][j]);
		}
	}
	return maxlcs;
}

int main() {

	int n;
	string S1, S2;

	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> S1 >> S2;
		cout << lcs(S1, S2) << endl;
	}

	return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;

string X, Y;
int v[1001][1001];

int  dp(string X, string Y) {
	int n = X.size();
	int m = Y.size();

	for (int i = 0; i < n; i++) {
		v[i][0] = 0;											///０のテーブル
		for (int j = 0; j < m; j++) {
			v[0][j] = 0;
		}
	}

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

int main(void)
{
	int x;
	cin >> x;

	for (int i = 0; i < x; i++) {
		cin >> X >> Y;
		int ans = dp(X, Y);
		cout << ans << endl;
	}
}

C++: #include<bits/stdc++.h>
#define dump(a) cout << #a << " " << a << endl
#define MAX_SIZE 1000
using namespace std;

string X,Y;
int dp[MAX_SIZE+1][MAX_SIZE+1];

int dfs(int xi, int yi) {
	if (dp[xi][yi] != -1) { return dp[xi][yi]; }

	if (xi==X.size() || yi==Y.size()) { return 0; }
	else if (X[xi] == Y[yi]) {
		dp[xi][yi] = dfs(xi+1,yi+1) + 1;
	}
	else {
		dp[xi][yi] = max(dfs(xi,yi+1),dfs(xi+1,yi));
	}
	return dp[xi][yi];
}

int main() {
	int N;

	cin >> N;

	for(int i=0; i<N; i++) {
		cin >> X >> Y;
		memset(dp,-1,sizeof(dp)); //-1??§?????????
		cout << dfs(0,0) << endl;
	}

	return EXIT_SUCCESS;
}

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

int lcs(string X, string Y) {
    int c[N + 1][N + 1];
    int m = X.size();
    int n = Y.size();
    int max1 = 0;
    X = ' ' + X;
    Y = ' ' + Y;
    for ( int i = 0; i <= m; i++ ) c[i][0] = 0;
    for ( int j = 0; 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]);
            }
            max1 = max(max1, c[i][j]);
        }
    }

    return max1;
}

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 <iostream>
#include <math.h>
#include <string>
#include <algorithm>
#include <set>
#include <queue>
#include <stack>
#include <utility>
#include <tuple>
using namespace std;

const double pi = acos(-1);
#define nyan cout<<"(=^•ω•^=)"<<endl;
#define int long long
#define rep(i,n) for(int i=0;i<n;i++)

int Q;
int dp[1100][1100];
// 1-leadingとして，
// dp[i][j] := sのi番目までの文字列とtのj番目までの文字列のLCSのサイズ

signed main(){
    cin>>Q;
    rep(q,Q){
        string s,t;
        cin>>s>>t;
        for(int i=0;i<=s.length();i++)dp[i][0]=0;
        for(int i=0;i<=t.length();i++)dp[0][i]=0;
        for(int i=1;i<=s.length();i++){
            for(int j=1;j<=t.length();j++){
                if(s[i-1]==t[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[s.length()][t.length()]<<endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
using namespace std;
 
static const long N = 1000;
 
long lcs(string X, string Y){
    long c[N + 1][N + 1];
    long m = X.size();
    long n = Y.size();
    long maxl = 0;
    X = ' ' + X;
    Y = ' ' + Y;
    for (long i = 1; i <= m; i++) c[i][0] = 0;
    for (long j = 1; j <= n; j++) c[0][j] = 0;
 
    for (long i = 1; i <= m; i++){
        for (long 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]);
            }
            maxl = c[i][j];
        }
    }
 
    return maxl;
}
 
int main(){
    string s1, s2;
    long n;
    cin >> n;
    for (long i = 0; i < n; i++){
        cin >> s1 >> s2;
        cout << lcs(s1, s2) << endl;
    }
    return 0;
}

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

int h[1001][1001];
string A;
string B;

void f(int i, int j) {
    if (A.at(i) == B.at(j)) {
            h[i][j] = h[i-1][j-1] + 1;
    } else {
        h[i][j] = max(h[i][j-1], h[i-1][j]);
    }
}

int lcs(string A, string B) {
    for (int i = 1; i <= A.length()-1; ++i) {
        for (int j = 1; j <= B.length()-1; ++j) {
            f(i, j);
        }

    }
    return h[A.length()-1][B.length()-1];
}

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

    for (int i = 0; i < n; ++i) {
        cin >> A;
        cin >> B;
        A = " " + A;
        B = " " + B;
        int a = lcs(A, B);
        cout << a << endl;
    }

    return 0;
}