Go: package main

import "fmt"

func initialize_grid(width int,height int)[][]int{
	var grid [][]int
	for i:=0;i<height+1;i++{
		var grid_row  []int
		for j:=0;j<width+1;j++{
			grid_row = append(grid_row,0)
		}
		grid = append(grid,grid_row[:])
	}
	return grid
}

func ma(x int,y int)int{
	if x >= y{
		return x
	}else{
		return y
	}
}

func main()  {
	//Take input
	var num int
	var st1,st2 string
	var string_pairs [][]string
	fmt.Scan(&num)
	for i:=0;i<num;i++{
		var string_pair []string
		fmt.Scan(&st1)
		fmt.Scan(&st2)
		string_pair = append(string_pair,st1,st2)
		string_pairs = append(string_pairs,string_pair)
	}
	//DP
	//initialize grid
	for i:=0;i<num;i++{
		string_1 := string_pairs[i][0]
		string_2 := string_pairs[i][1]

		dp := initialize_grid(len(string_2),len(string_1))

		for j:=1;j<len(string_1)+1;j++{
			for k:=1;k<len(string_2)+1;k++{
				if string_1[j-1] == string_2[k-1]{
					dp[j][k] = dp[j-1][k-1] + 1
				}else{
					dp[j][k] = ma(dp[j-1][k],dp[j][k-1])
				}
			}
		}
		fmt.Println(dp[len(string_1)][len(string_2)])
	}
}

C++: /**Function Template**/
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> pint;
const int MAX = 510000;
const int MOD = 1000000007;
#define rep(i, n) for(ll i = ll(0); i < ll(n); i++)
#define Rep(i, n) for(ll i = ll(1); i < ll(n); i++)
#define ALL(a)  (a).begin(),(a).end()
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define PI 3.14159265358979323846
#define ifYN(x) cout<<(x?"Yes":"No")<<"\n" 
ll fac[MAX], finv[MAX], inv[MAX];


template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

bool palindrome(string s){
  bool flag=true;
  rep(i,(ll)s.size()) if(s[i]!=s[s.size()-1-i]) flag=false;
  return flag;
}

// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (ll i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }

}
ll Len(ll n) {
  ll s=0;
  while(n!=0) s++, n/=10;
  return s;
}


ll Sint(ll n) {
  ll ans=0;
  while(n!=0) ans+=n%10,n/=10;
  return ans;
}

ll Svec(vector<ll> v){
  ll n=0;
  rep(i,(ll)v.size()) n+=v[i];
  return n;
}


ll GCD(ll a,ll b) {
  return b ? GCD(b,a%b) : a;
}


ll LCM(ll a,ll b){
  return a/GCD(a,b)*b;
}


ll Factorial(ll n){
  ll m=1;
  while(n>=1) m*=n,n--;
  return m;
}

void runlength(string s,vector<pair<char,ll>> &p){
  ll x=1;
  if(s.size()==1){
    p.push_back(pair<char,ll>(s[0],1));
  }
  rep(i,(ll)s.size()-1){
    if(s[i]==s[i+1]){
      x++;
      if(i==(ll)s.size()-2){
        p.push_back(pair<char,ll>(s[i],x));
      }
    }else{
      p.push_back(pair<char,ll>(s[i],x));
      x=1;
      if(i==(ll)s.size()-2){
        p.push_back(pair<char,ll>(s[s.size()-1],x));
      }
    }
  }
}

ll COM(ll n,ll k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

ll modpow(ll a, ll n, ll mod) {
    ll res = 1;
    while (n > 0) {
        if (n & 1) res = res * a % mod;
        a = a * a % mod;
        n >>= 1;
    }
    return res;
}

string Toupper(string s){
  string ans="";
  rep(i,s.size()){
    if('a'<=s[i] && s[i]<='z') ans+=(char)s[i]-32;
    else ans+=s[i];
  }
  return ans;
}
string Tolower(string s){
  string ans="";
  rep(i,s.size()){
    if('A'<=s[i] && s[i]<='Z') ans+=(char)s[i]+32;
    else ans+=s[i];
  }
  return ans;
}

void dis(vector<ll> v){ rep(i,v.size()) cout<<v[i]<<endl; }

void dis2(vector<vector<ll>> v){
  rep(i,v.size()){
    rep(j,v[0].size()) cout<<v[i][j]<<' ';
    cout<<endl;
  }
}

const int MAX_N=100010;
vector<bool> sieve_of_eratosthenes(){
  vector<bool> isPrime(MAX_N+1,true);
  /* isPrime[1]=false; */
  for(int i=2;i<=MAX_N;i++){
    if(isPrime[i]){
      for(int j=2*i;j<=MAX_N;j+=i){
        isPrime[j]=false;
      }
    }
  }
  return isPrime;
}

vector<pint> prime_factorize(ll n){
  vector<pint> ans;
  for(ll p=2;p<=sqrt(n);p++){
    if(n%p!=0) continue;
    ll cnt=0;
    while(n%p==0){
      n/=p;
      cnt++;
    }
    ans.push_back(make_pair(p,cnt));
  }
  if(n!=1) ans.push_back(make_pair(n,1));
  return ans;
}

/*bool cmp(pint a, pint b) { return a.second < b.second; }*/

/*↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓*/
int main() {
  IOS;
  ll n;
  cin>>n;
  rep(_,n){
    string s,t;cin>>s>>t;ll a=s.size(),b=t.size();
    vector<vector<ll>> dp(a+1,vector<ll>(b+1,0));
    rep(i,a){
      rep(j,b){
        if(s[i]==t[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[a][b]<<endl;
  }
}

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

int lcs(string X, string Y) {
	int c[1000][1000];
	int m = X.length();
	int n = Y.length();
	int maxl = 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++) {
			cout << c[i][j];
			if (X[i] == Y[j]) {
				c[i][j] = c[i - 1][j - 1] + 1;
			}
			else if (c[i - 1][j] >= c[i][j - 1]) {
				c[i][j] = c[i - 1][j];
			}
			else {
				c[i][j] = c[i][j - 1];
			}

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

int main() {
	int n;
	string x, y;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x >> y;

		cout << lcs(x, y) << endl;
	}

	
}

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

int count(const string& X, int i, const string Y, int j){
    if (i >= X.size() || j >= Y.size()) return 0;
    while (X[i] != Y[j]) {
        j++;
        if (j >= Y.size()) return 0;
    }
    return 1 + count(X, i + 1, Y, j + 1);
}

int solve(const string& X, const string& Y) {
    int max = 0;
    for (int i = 0; i < X.size(); i++) {
        int c = count(X, i, Y, 0);
        if (c > max) max = c;
    }
    return max;
}

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

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 maxl = 0;
  X = ' ' + X;
  Y = ' ' + Y;
  c[0][0] = 0;
  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]);
      }
      maxl = max(maxl, c[i][j]);
    }
  }

  return maxl;
}

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>
#define INF 1000000
using namespace std;

int q;
string x,y;
int _dp[1010][1010];
int result[150];

int dp(int posx,int posy){
	if(_dp[posx][posy]) return _dp[posx][posy];
	if(posx == 0 || posy == 0){
		_dp[posx][posy] == 0;
		return 0;
	}else{
		int max = dp(posx-1,posy);
		if(max < dp(posx,posy-1)) max = dp(posx, posy-1);
		if(x[posx-1] == y[posy-1] && max < dp(posx-1,posy-1)+1)
			max = dp(posx-1,posy-1)+1;
		_dp[posx][posy] = max;
		return max;
	}
}

int main(void){
	cin >> q;
	
	for(int i=0; i<q; i++){
		cin >> x >> y;
		result[i] = dp(x.size() ,y.size());
		std::fill((int*) _dp, (int*) (_dp + 1010), 0);
	}
	
	for(int i=0; i<q; i++) cout << result[i] << endl;
	
	return 0;
}