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>
#include<unordered_set>
#include<unordered_map>
#include <algorithm> 
#include <iostream>
#include <string>
#include <cmath>
using namespace std;
#define ll long long
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define FOR(i,a,b) for(ll i=(a);i<(b);i++)
#define FORR(i,a,b)for(ll i=(a);i<=(b);i++)
#define repR(i,n) for(ll i=n;i>=0;i--)
#define all(v)(v).begin(),(v).end()
#define rall(v)(v).rbegin(),(v).rend()
#define F first
#define S second
#define pb push_back
#define pu push
#define COUT(x) cout<<(x)<<endl
#define PQ priority_queue<ll>
#define PQR priority_queue<ll,vector<ll>,greater<ll>>
#define YES(n) cout << ((n) ? "YES" : "NO"  ) << endl
#define Yes(n) cout << ((n) ? "Yes" : "No"  ) << endl
#define mp make_pair
#define maxs(x,y) (x = max(x,y))
#define mins(x,y) (x = min(x,y))
#define sz(x) (ll)(x).size()
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MOD = 1000000007LL;
const ll INF = 1LL << 60;
using vll = vector<ll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvll = vector<vll>;
using vstr = vector<string>;
using pll = pair<ll, ll>;
using vc = vector<char>;
using vvc = vector<vc>;
template<class T> inline bool chmax(T& a, T b) { 
if (a < b) { a = b; return true; } return false; 
}
template<class T> inline bool chmin(T& a, T b) {
 if (a > b) { a = b; return true; } return false; 
 }
ll dx[4]={0,1,0,-1};
ll dy[4]={1,0,-1,0};
ll dp[1005][1005];
ll res(string a,string b){
  memset(dp,0,sizeof(dp));
  rep(i,sz(a))rep(j,sz(b)){
    if(a[i]==b[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]);
  }
  return dp[sz(a)][sz(b)];
}
int main(){
  ll q;
  cin>>q;
  rep(i,q){
    string a,b;
    cin>>a>>b;
    COUT(res(a,b));
  }
}

C++: #include<stdio.h>
#include<string.h>
    
int LCS(char *X, char *Y){
  int i,j,m,n,c[1001][1001];
  m = strlen(X);
  n = strlen(Y);
      
  for(i=0; i<m; i++){
    c[i][0] = 0;
  }
  for(j=0; j<n; j++){
    c[0][j] = 0;
  }
    
  for(i=1;i<m+1;i++){
    for(j=1;j<n+1;j++){
      if (X[i-1]==Y[j-1]) 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];
    }
  }
  return c[i-1][j-1];
}
    
int main(){
  int i, q;
  char X[1001], Y[1001];
      
  scanf("%d", &q);
  for(i=0; i<q; i++){
    scanf("%s", X);
    scanf("%s", Y);
    printf("%d\n", LCS(X, Y));
    
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int main(){
  string  a,b;
  long n=0,i,c=0;
  cin>>a>>b;
  for(i=0;i<a.size();i++)if(a[i]==b[c])if(++n)c++;
  cout<<n<<endl;
}

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

int DP[1010][1010];

int main() {
  int n;
  cin >> n;
  for (auto t=0; t<n; t++) {
    string A, B;
    cin >> A >> B;
    int LA = (int) A.size();
    int LB = (int) B.size();
    fill(&DP[0][0], &DP[0][0]+1010*1010, 0);
    for (auto i=-1; i<LA; i++) {
      for (auto j=-1; j<LA; j++) {
        if (i == -1 || j == -1) {
          DP[i+1][j+1] = 0;
        } else if (A[i] == B[j]) {
          DP[i+1][j+1] = 1 + DP[i][j];
        } else {
          DP[i+1][j+1] = max(DP[i+1][j], DP[i][j+1]);
        }
      }
    }
    cout << DP[LA][LB] << endl;
  }
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
int main(){
    int n,i,j;string s,t;cin >> n;
    while(cin >> s >> t){
        int dp[s.size()+1][t.size()+1] = {};
        for(i=1;i<=s.size();i++){
            for(j=1;j<=t.size();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.size()][t.size()] << endl;
    }
}

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

#define rep(i, n) for (int i=0; i<(n); ++i)
using ll = long long;
using P = pair<int, int>;

const int MAX = 1003;
int dp[MAX][MAX];

int lcs(string x, string y) {
  int m = x.length();
  int n = y.length();
  x = ' ' + x;
  y = ' ' + y;
  rep(i,m+1) dp[i][0] = 0;
  rep(i,n+1) dp[0][i] = 0;

  int ans = 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]);
      //printf("[*] %d %d %d\n", i, j, dp[i][j]);
      ans = max(ans, dp[i][j]);
    }
  }

  return ans;
}

int main() {
  int n;
  cin >> n;
  string x, y;
  vector<int> ans;
  rep(i,n) {
    cin >> x;
    cin >> y;
    ans.push_back(lcs(x, y));
  }

  rep(i,ans.size()) cout << ans[i] << endl;
  return 0;
}

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

int lcs(string a,string b){
  int c[1001][1001];
  int m=a.size(),n=b.size();
  int mx=0;
  a=' '+a;
  b=' '+b;
  for(int i=1;i<=m;i++){
    for(int j=1;j<=n;j++){
      if(a[i]==b[j]){
	c[i][j]=c[i-1][j-1]+1;
      }else{
	c[i][j]=max(c[i-1][j],c[i][j-1]);
      }
      mx=max(mx,c[i][j]);
    }
  }
  return mx;
}


int main(){
  int q;
  string s1,s2;
  cin>>q;
  for(int i=0;i<q;i++){
    cin>>s1>>s2;
    cout<<lcs(s1,s2)<<endl;
  }
  return 0;
}

C++: #include <iostream>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <bitset>
#include <algorithm>
#include <complex>
#include <array>
#include <iomanip>
using namespace std;

#define REP(i,n) for(int i=0; i<n; ++i)
#define FOR(i,a,b) for(int i=a; i<=b; ++i)
#define FORR(i,a,b) for (int i=a; i>=b; --i)
#define ALL(c) (c).begin(), (c).end()

typedef long long ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<long double> VD;
typedef vector<VI> VVI;
typedef vector<VL> VVL;
typedef vector<VD> VVD;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;

template<typename T> void chmin(T &a, T b) { if (a > b) a = b; }
template<typename T> void chmax(T &a, T b) { if (a < b) a = b; }

int in() { int x; scanf("%d", &x); return x; }
ll lin() { ll x; scanf("%lld", &x); return x; }
#define INF 1LL<<60

int main() {
    int Q;
    cin >> Q;
    REP(q, Q) {
        string X, Y;
        cin >> X >> Y;
        int len_x = X.length(), len_y = Y.length();
        vector<vector<int>> dp(len_x + 1, vector<int>(len_y + 1));

        FOR(i, 1, len_x)
             FOR(j, 1, len_y) {
                 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[len_x][len_y] << endl;
    }
    return 0;
}

C++: #include "iostream"
#include "string.h"

using namespace std;

int L[1001][1001];

int lcs( char s1[], char s2[], int l1, int l2 ) {

	if (L[l1][l2] != 0)return L[l1][l2];

	if (l1 == 0 || l2 == 0) return 0;
	else if (s1[l1-1] == s2[l2-1]) L[l1][l2] = lcs(s1, s2, l1 - 1, l2 - 1) + 1;
	else {
		int lsc1 = lcs(s1, s2, l1 - 1, l2);
		int lsc2 = lcs(s1, s2, l1, l2 - 1);

		if (lsc1 > lsc2) L[l1][l2] = lsc1;
		else L[l1][l2] = lsc2;
	}

	return L[l1][l2];
}

int main() {

	int n;
	char s1[1000], s2[1000];

	cin >> n;

	int ans[150];

	for (int i = 0; i < n; i++) {
		cin >> s1;
		cin >> s2;

		ans[i] = lcs(s1, s2, strlen(s1), strlen(s2));
	}

	for (int i = 0; i < n; i++) {
		cout << ans[i] << endl;
	}

	return 0;
}