Go: package main

import "fmt"

func main() {
	var nPairs int
	fmt.Scanln(&nPairs)

	var a, b string
	for i := 0; i < nPairs; i++ {
		fmt.Scanln(&a)
		fmt.Scanln(&b)
		fmt.Println(lcsSize(a, b))
	}
}

func lcsSize(sa, sb string) int {
	dp := make([][]int, len(sa)+1)
	for i := 0; i <= len(sa); i++ {
		dp[i] = make([]int, len(sb)+1)
	}

	for a := 1; a <= len(sa); a++ {
		for b := 1; b <= len(sb); b++ {
			if sa[a-1] == sb[b-1] {
				dp[a][b] = dp[a-1][b-1] + 1
			} else {
				dp[a][b] = max(dp[a][b-1], dp[a-1][b])
			}
		}
	}

	return dp[len(sa)][len(sb)]
}

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

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <math.h>
#include <string>
#include <utility>
using namespace std;

int n;
string a,b;


int main(){
	cin >> n;
	for (int i = 0; i < n; i++){
		cin >> a >> b;
		int t[1010][1010] = {};
		for (int i = 0; i < a.length(); i++){
			for (int j = 0; j < b.length(); j++){
				if (i == 0 || j == 0)t[i][j] = 0;
				else if (a[i] == b[i]){
					t[i + 1][j + 1] = t[i][j] + 1;
				}
				else t[i + 1][j + 1] = max(t[i + 1][j], t[i][j + 1]);
			}
		}
		cout << t[a.length()][b.length()] << endl;
	}
	return 0;
}

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

int main() {
  int q;
  cin >> q;
  for (int i=0;i<q;++i) {
    string str1,str2;
    cin >> str1 >> str2;
    int size1 = str1.size();
    int size2 = str2.size();
    int matrix[size1+1][size2+1];
    for (int j=0;j<=size1;++j)
      matrix[j][0] = 0;
    for (int j=0;j<=size2;++j)
      matrix[0][j] = 0;
    for (int j=0;j<=size1;++j) {
      for (int k=0;k<=size2;++k) {
	if (j<=0||k<=0) {
	  matrix[j][k] = 0;
	}
	else if (str1[j]==str2[k]) {
	  matrix[j][k] = 1 + matrix[j-1][k-1];
	}
	else {
	  matrix[j][k] = max(matrix[j][k-1],matrix[j-1][k]);
	}
      }
    }
    cout << matrix[size1][size2] << endl;
  }
}

int max(int a,int b) {
  if (a>b)
    return a;
  else
    return b;
}

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

int main()
{
    int q;
    cin >> q;
    for (int ii = 0; ii < q; ii++)
    {
        string X, Y;
        cin >> X >> Y;
        int x = X.size();
        int y = Y.size();
        int dp[x + 1][y + 1];
        memset(dp, 0, sizeof(dp));
        for (int i = 0; i < x; i++)
        {
            for (int j = 0; j < y; j++)
            {
                if (X[i] == Y[j])
                {
                    dp[i + 1][j + 1] = max({dp[i][j] + 1, dp[i + 1][j], dp[i][j + 1]});
                }
                else
                {
                    dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
                }
            }
        }
        cout << dp[x][y] << endl;
    }
}

C++: // Longest Common Subsequence

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<string>
using namespace std;
#define MAX 1001

int make_lcs(string x, string y) {
	int lcs[MAX][MAX] = {};
	x = ' ' + x;
	y = ' ' + y;
	for (unsigned int i=0;i<x.length();i++) {
	for (unsigned int j=0;j<y.length();j++) {
	if (i!=0 && j!=0) {
	if (x[i] == y[j]) {
	lcs[i][j] = lcs[i-1][j-1] + 1;
	}
	else {
	lcs[i][j] = max(lcs[i-1][j], lcs[i][j-1]);
	}
	}
	}
	}
	return lcs[x.length()-1][y.length()-1];
}
int main() {
	int n;
	string x,y;
	cin >> n;
	for (int k=0;k<n;k++) {
	cin >> x >> y;
	cout << make_lcs(x,y) << endl;
	}
	return 0;
}

C++: #include "bits/stdc++.h"
 
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef pair<int,int> pii;
#define int ll
#define fi first
#define se second
#define SORT(a) sort(a.begin(),a.end())
#define rep(i,n) for(int i = 0;i < (n) ; i++) 
#define REP(i,n) for(int i = 0;i < (n) ; i++) 
#define MP(a,b) make_pair(a,b)
#define pb(a) push_back(a)
#define INF LLONG_MAX/2
#define all(x) (x).begin(),(x).end()
#define debug(x) cerr<<#x<<": "<<x<<endl
#define debug_vec(v) cerr<<#v<<":";rep(i,v.size())cerr<<" "<<v[i];cerr<<endl
/*----------------------------------------------------------------*/

// int MOD = 998244353;
int MOD = 1000000007;

int dp[1010][1010] = {};



/*----------------------------------------------------------------*/
signed main(){

    int q;
	cin >> q;
	rep(iii,q){
		string s,t;
		cin >> s >> t;
		int sl = s.size();
		int tl = t.size();
		rep(i,sl)rep(j,tl)dp[i][j] = 0;
		rep(i,sl){
			rep(j,tl){
				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[sl][tl] << endl;
	}
	
	

	return 0;
}
/*----------------------------------------------------------------*/

// g++ -std=c++14 code1.cpp
// sudo pip3 install --upgrade online-judge-tools
// rm -r -f test;oj dl https://code-festival-2018-quala.contest.atcoder.jp/tasks/code_festival_2018_quala_c
// rm -r -f test;oj dl https://pakencamp-2019-day3.contest.atcoder.jp/tasks/pakencamp_2019_day3_c
// rm -r -f test;oj dl https://abc088.contest.atcoder.jp/tasks/abc088_d

C++: // aribon2-3-2_a
#include <bits/stdc++.h>
#ifdef LOCAL
#include "../cxx-prettyprint/prettyprint.hpp"
#endif
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;

#define REP(i, n) for (int (i) = 0 ; (i) < (int)(n) ; ++(i))
#define REPN(i, m, n) for (int (i) = m ; (i) < (int)(n) ; ++(i))
#define REP_REV(i, n) for (int (i) = (int)(n) - 1 ; (i) >= 0 ; --(i))
#define REPN_REV(i, m, n) for (int (i) = (int)(n) - 1 ; (i) >= m ; --(i))
#define ALL(x) x.begin(), x.end()

#define INF ((1 << 29)-1)
#define MOD (1000000007)

#define print2D(h, w, arr) REP(i, h) { REP(j, w) cout << arr[i][j] << " "; cout << endl; }
template<class T> void print(const T& x){cout << x << endl;}
template<class T, class... A> void print(const T& first, const A&... rest) { cout << first << " "; print(rest...); }
struct PreMain {PreMain(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(20);}} premain;

int main() {
#ifdef LOCAL
    ifstream in("../arg.txt");
    cin.rdbuf(in.rdbuf());
#endif

    int N;
    cin >> N;
    string A,B;
    REP(n, N){
        cin >> A >> B;
        int dp[A.size()+1][B.size()+1] = {};

        REP(i, A.size()){
            REP(j, B.size()){
                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]);
                }

            }
        }
        print(dp[A.size()][B.size()]);
    }

    return 0;
}

C++: #include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <functional>

using namespace std;
using ll = long long int;
#define rep(i,n) for(int i = 0; i < n; i++)
#define FOR(i, a, b)  for(int i = (a); i < (b) ; i++)
#define pb push_back
#define SORT(v,n) sort(v, v+n)
#define ALL(x) (x).begin(),(x).end()
#define debug(x) cerr << #x << ": " << x << '\n'
#define elif else if
#define itn ll
#define int ll
const int INF = 100100100;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
///                →,↑,←,↓,↗,↖,↙,↘
int dx[8] = { 1, 0, -1, 0, 1, -1, -1, 1 };
int dy[8] = { 0, 1, 0, -1, 1, 1, -1, -1 };


static const int N = 1000;

int lcs(string X, string Y) {
	int c[N + 1][N + 1];
	int maxl = 0;
	int i, j;
	int m = X.size();
	int n = Y.size();
	X = ' ' + X;
	Y = ' ' + Y;
	FOR(i, 1, m+1) {
		c[i][0] = 0;
	}
	FOR(i, 1, n+1) {
		c[0][i] = 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(c[i][j], maxl);
		}
	}
	return maxl;
}

signed main() {
	ios::sync_with_stdio(false);
	int n;
	string s1, s2;
	cin >> n;
	int i;
	rep(i, n) {
		cin >> s1 >> s2;
		cout << lcs(s1, s2) << "\n";
	}
	return 0;
}