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<string>

using namespace std;

#if 0
http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=2065462#1
#endif

int n;
string a, b;
string x[10000], y[10000];




int main(){
  cin >> n;
  while(n != 0){
    n = n -1;
    int longest[1000][1000];
    cin >> a;
    cin >> b;
    a = ' ' + a;
    b = ' ' + b;
    int mm = 0;
    /*
    for(int i = 0; i < a.size(); ++i){
      for(int j = 0; j < b.size(); ++j){
        
        x[i] = a;
        y[j] = b;
      }
    }
    */
   //longest[0][0] =0;
   for(int i = 1; i <= a.size(); ++i){
     longest[i][0] = 0;
    }
   for(int j = 1; j <= b.size(); ++j){
     longest[0][j] = 0;
   }
    for(int i = 1; i <= a.size(); ++i){
      for(int j = 1; j <= b.size(); ++j){
        
        /*
        if(i <= 0 || j <=0){
          longest[i][j] = 0;
        }
        */
        if(a[i] == b[j]){
          longest[i][j] = 1 + longest[i-1][j - 1];
        }
        else{
          longest[i][j] = max(longest[i][j-1], longest[i-1][j]);
        }
        mm = max(mm, longest[i-1][j-1]);
      }
    }
    //cout << a[1] << endl;
    cout << mm << endl;
  }
}

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

using namespace std;

int main() {
    int Q = 0;
    string X,Y;
    cin>>Q;
    for (int q = 0; q < Q; q++) {
        cin>>X>>Y;

        int len[1001][1001] = {};
        for (int s = 1; s <= X.length(); s++) {
            for (int t = 1; t <= Y.length(); t++) {
                if (X[s] == Y[t]) len[s][t] = 1 + len[s-1][t-1];
                else len[s][t] = max(len[s-1][t], len[s][t-1]);
            }
        }
        cout<<len[X.length()][Y.length()]<<endl;
    }
}

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.length();
	int n = Y.length();
	int maxlen = 0;
	X = ' ' + X;
	Y = ' ' + Y;
	for (int i = 0; i < m + 1; i++)c[i][0] = 0;
	for (int j = 1; j < n + 1; j++)c[0][j] = 0;

	for (int i = 1; i < m + 1; i++) {
		for (int j = 1; j < n + 1; 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]);
			}
			maxlen = max(maxlen, c[i][j]);
		}
	}
	return c[m][n];
}

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

C++: #include<iostream>
#include<iomanip>
#include<algorithm>
#include<bitset>
#include<cctype>
#include<climits>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<deque>
#include<list>
#include<map>
#include<set>
#include<stack>
#include<string>
#include<sstream>
#include<queue>
#include<vector>
using namespace std;

//????????±?????¨??????
int lcs(string X, string Y) {
	static const int MAX_X = 1000, MAX_Y = 1000;
	static int dp[MAX_X + 1][MAX_Y + 1];
	memset(dp, 0, sizeof(dp));
	for (int i = 1; i <= X.size(); i++) {
		for (int j = 1; j <= Y.size(); j++) {
			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]
				);
			}
		}
	}
	return dp[X.size()][Y.size()];
}

int main() {
	int q; cin >> q;
	while (q--) {
		string X, Y; cin >> X >> Y;
		cout << lcs(X, Y) << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
template<class T> inline bool chmax(T &a, T b) { if (a<b) {a=b; return 1;} return 0;}
template<class T> inline bool chmin(T &a, T b) { if (b<a) {a=b; return 1;} return 0;}

int dp[1010][1010];

void solve() {
    string s, t;
    cin >> s >> t;
    memset(dp, 0, sizeof(dp));
    rep(i, s.size()) {
        rep(j, t.size()) {
            if (s[i] == t[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]);
        }
    }
    cout << dp[s.size()][t.size()] << endl;
}

int main() {
    int q;
    cin >> q;
    rep(i, q) solve();
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <string>
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>

using namespace std;

// ---------------------
// repetition
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

// debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

// ---------------------
#define INF 922337203685477580
typedef long long ll;

int dp[1000][1000];

int main() {
  int q;
  cin >> q;
  REP(loop, q) {
    char S[1000], T[1000];
    cin >> S >> T;

    FOR(i, strlen(S)) {
      FOR(j, strlen(T)) {
        dp[i][j] = 0;
      }
    }
    for (int i = 0; i < strlen(S); i++) {
      for (int j = 0; j < strlen(T); j++) {
        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[strlen(S) - 1][strlen(T) - 1] << endl;
  }

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int C[1000][1000];
int lc(string F, string S){
    fill(C[0],C[1000],0);
    int m = F.size(), n = S.size();
    int len=0;
    for(int i=0; i<m; i++){
        for (int j = 0; j < n; ++j) {
            if (F[i] == S[j]) {
                if (i - 1 >= 0 && j - 1 >= 0)
                    C[i][j] = C[i - 1][j - 1] + 1;
                else
                    C[i][j] = 1;
            } else if (i - 1 >= 0 && j - 1 >= 0) {
                C[i][j] = max(C[i-1][j], C[i][j - 1]);
            }
            len = max(len, C[i][j]);
        }
    }
    return len;
}

int main() {
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    string ar[n*2];
    for (int i = 0; i < n * 2; ++i) {
        cin >> ar[i];
    }
    for (int j = 0; j < n*2; j+=2) {
        cout << lc(ar[j],ar[j+1]) << endl;
    }
    return 0;
}