Go: package main

import "fmt"

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

	for q := 0; q < n; q++ {
		var s1, s2 string
		fmt.Scan(&s1, &s2)
		s1, s2 = " " + s1, " " + s2

		dp := make([][]int, len(s1))
		for i := range dp {
			dp[i] = make([]int, len(s2))
		}

		max := 0

		for i := 1; i < len(s1); i++ {
			for j := 1; j < len(s2); j++ {
				if s1[i] == s2[j] {
					dp[i][j] = dp[i-1][j-1] + 1
				} else {
					dp[i][j] = Max(dp[i-1][j], dp[i][j-1])
				}
				max = Max(max, dp[i][j])
			}
		}

		fmt.Println(max)
	}
}

func Max(n ...int) int {
	max := n[0]
	for _, v := range n[1:] {
		if v > max {
			max = v
		}
	}
	return max
}

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

void fnInput(vector<string>& rvsStrX, vector<string>& rvsStrY)
{
  int nMaxSiz;
  cin >> nMaxSiz;
  rvsStrX.resize(nMaxSiz);
  rvsStrY.resize(nMaxSiz);

  for (int i = 0; i < nMaxSiz; ++i)
  {
    cin >> rvsStrX[i] >> rvsStrY[i];
    rvsStrX[i] = ' ' + rvsStrX[i];
    rvsStrY[i] = ' ' + rvsStrY[i];
  }
}

int fnLngCmnSubseq(const vector<string>& cnrvsStrX, const vector<string>& cnrvsStrY)
{
  vector<vector<int>> vvnLcsDP;
  for (int i = 0; i < cnrvsStrX.size(); ++i)
  {
    const int nMAXNX = cnrvsStrX[i].size();
    const int nMAXNY = cnrvsStrY[i].size();

    vvnLcsDP.clear();
    vvnLcsDP.resize(nMAXNX, vector<int>(nMAXNY, 0));

    for (int nx = 1; nx < nMAXNX; ++nx)
      for (int ny = 1; ny < nMAXNY; ++ny)
        if (cnrvsStrX[i][nx] == cnrvsStrY[i][ny])
          vvnLcsDP[nx][ny] = vvnLcsDP[nx - 1][ny - 1] + 1;
        else
          vvnLcsDP[nx][ny] = max(vvnLcsDP[nx - 1][ny], vvnLcsDP[nx][ny - 1]);

    cout << vvnLcsDP[nMAXNX - 1][nMAXNY - 1] << endl;
  }
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<string> vsStrX, vsStrY;

  fnInput(vsStrX, vsStrY);
  fnLngCmnSubseq(vsStrX, vsStrY);
  return 0;
}

C++: #define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define int long long
#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a,b) for(int i=a;i<=b;i++)
#define rev(i,n) for(int i=n-1;i>=0;i--)
#define vi vector<int>
#define pb push_back
#define pi pair<int,int>
#define vp vector<pair<int,int> >
#define mp make_pair
#define all(v) (v).begin(),(v).end()
#define fi first
#define se second
#define MEMSET(a) memset(a,0,sizeof(a))
#define inf (1ll<<60)

using namespace std;

const int mod=1e9+7;

void run();

void init() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout<<fixed<<setprecision(12);
}

signed main(){
    init();
    run();
    return 0;
}

void run(){
    int q;
    cin>>q;
    while(q--){
        string x,y;
        cin>>x>>y;
        int n=x.length(),m=y.length();
        int dp[n+1][m+1];
        MEMSET(dp);
        REP(i,1,n){
            REP(j,1,m){
                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[n][m]<<endl;
    }
}

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

int main()
{
    int N;
    cin >> N;
    for(int k=0;k<N;k++)
    {
        string word1,word2;
        cin >> word1;
        cin >> word2;
        int L[2000][2000];
        for(int i=0;i<word1.size();i++)
           for(int j=0;j<word2.size();j++)
           {
               if(i<0 || j<0 )
                 L[i][j]=0;
               else if(word1[i]==word2[j])
                 L[i][j]=1+L[i-1][j-1];
               else
                 L[i][j]=max(L[i-1][j],L[i][j-1]);
           }
        cout << L[word1.size()-1][word2.size()-1] << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int lcs(string s1, string s2){
    int n=s1.size();
    int m=s2.size();

    s1=' '+s1;
    s2=' '+s2;

    int dp[n+1][m+1];
    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(s1[i]==s2[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(void){
    int n; cin >> n;
    for(int i=0; i<n; i++){
        string s1,s2; cin >> s1 >> s2;
        cout << lcs(s1,s2) << endl;
    }
}

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

int dp[1001][1001] = {{0}};

int LCS(const string & X, const string & Y){
    auto len_x = X.length();
    auto len_y = Y.length();
    for (int i = 0; i != len_x; ++i){
        for (int j = 0; j != len_y; ++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[len_x][len_y];
}

int main()
{
    ios::sync_with_stdio(false);
    
    int q = 0;
    cin >> q;
    
    string X;
    string Y;
    while (q--){
        cin >> X >> Y;
        cout << LCS(X, Y) << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <cstdio>
#include <vector>
#include <queue>
#include <map>
using namespace std;

bool findSubStr(string& shortword, vector<vector<int> >& charMap) {
	int i,j;
	j=0;
	for(i=0; i<(int)shortword.size(); ++i) {
		if(charMap[shortword[i]-'a'].empty()) return false;
		auto itr=charMap[shortword[i]-'a'].begin();
		while(itr!=charMap[shortword[i]-'a'].end()) {
			if(*itr<j) {
				++itr;
			} else {
				break;
			}
		}
		if(itr==charMap[shortword[i]-'a'].end()) return false;
		j=*itr;
	}
	return true;
}

int longestSQ(string& shortword, string& longword) {
	int i,j;
	string tempstr,prestr;
	vector<vector<int> > charMap(26);
	queue<string> targetword;
	map<string,bool> inqueue;
	for(i=0; i<(int)longword.size(); ++i) {
		charMap[longword[i]-'a'].push_back(i);
	}
	targetword.push(shortword);
	while(!targetword.empty()) {
		tempstr=targetword.front();
		if(findSubStr(tempstr,charMap)) return (int)tempstr.size();
		j=(int)tempstr.size();
		for(i=0; i<j; ++i) {
				tempstr=targetword.front();
				if(i==0 || tempstr[i]!=tempstr[i-1]) {
					tempstr.erase(tempstr.begin()+i);
					if(inqueue.find(tempstr)==inqueue.end()) {
						targetword.push(tempstr);
						inqueue[tempstr]=true;
					}
				}
		}
		targetword.pop();
	}
	return 0;
}

int main() {
	int i,q;
	cin >> q;
	string wordA,wordB;
	for(i=0; i<q; ++i) {
		cin >> wordA >> wordB;
		if(wordA.size()<wordB.size()) {
			printf("%d\n",longestSQ(wordA,wordB));
		} else {
			printf("%d\n",longestSQ(wordB,wordA));
		}
	}
	return 0;
}

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

int memo[1001][1001];
string s,t;

int dfs(int i, int j)
{
    if(i == 0 || j == 0) return 0;
    
    if(memo[i][j] != -1)return memo[i][j];
    
    int res = 0;
    
    if(s[i-1] == t[j-1]) res = dfs(i-1, j-1) + 1;
    else {
        res = max(dfs(i - 1, j), dfs(i, j - 1));
    }
    return memo[i][j] = res;
}

int main()
{
    int n;
    cin >> n;
    for(int i = 0; i < n; ++i){
        cin >> s >> t;
        fill((int*)memo, (int*)(memo + (int)max(s.size(), t.size()) + 1), -1);
        cout << dfs(s.size(), t.size()) << endl;
    }
}

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

using namespace std;

int lic(string X,string Y) {
	int c[1001][1001];
	int m = X.size();
	int n = Y.size();
	int maxl = 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]);
			}
		maxl=max(maxl,c[i][j]);
		}
	}
	return maxl;
}

int main() {
	string X, Y;
	int n;
	cin >> n;
	for (int i = 0;i < n;i++) {
		cin >> X >> Y;
		cout << lic(X, Y)<<endl;
	}
	return 0;
}