Go: package main

import (
	"bufio"
	"os"
	"strconv"
	"fmt"
)

func max(x, y int) int {
	if x < y {
		return y
	} else {
		return x
	}
}

/*********************************************************************
長さmの列X_(m)と長さnの列Y_(n)の最長共通部分列LCSは、
	(1)X[m] == Y[n]ならば、X_(m-1)とY_(n-1)のLCSにX[m]を繋げたもの
	(2)X[m] != Y[n]ならば、X_(m-1)とY_(n)のLCSもしくはX_(m)とY_(n-1)のLCS
	のいずれかのうち長い方

c[m+1][n+1]：c[i][j]にX_(i)とY_(j)のLCSの長さを格納する二次元配列
*********************************************************************/

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Scan()
	n, _ := strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		scanner.Scan()
		s1 := scanner.Text()
		scanner.Scan()
		s2 := scanner.Text()
		s1, s2 = s1 + " ", s2 + " "
		c := make([][]int, len(s1))
		for i := range c {
			c[i] = make([]int, len(s2))
		}

		LCS := 0

		for i := 1; i < len(s1); i++ {
			for j := 1; j < len(s2); j++ {
				if s1[i] == s2[j] {
					c[i][j] = c[i-1][j-1] + 1
				} else {
					c[i][j] = max(c[i-1][j], c[i][j-1])
				}
				LCS = max(LCS, c[i][j])
			}
		}
		fmt.Println(LCS)
	}
}

C++: //
// Created by ?????°?????? on 2016/04/21.
//

#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;
    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 = 0; 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 <bits/stdc++.h>
using namespace std;

long lcs(string x, string y) {
    long m = x.size();
    long n = y.size();
    x = ' ' + x;
    y = ' ' + y;
    long dp[m + 1][n + 1];
    for (long i = 0; i <= m; i++) {
        dp[i][0] = 0;
    }
    for (long i = 0; i <= n; i++) {
        dp[0][i] = 0;
    }

    long lcs_max = 0;
    for (long i = 1; i <= m; i++) {
        for (long 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]);
            }
            lcs_max = max(lcs_max, dp[i][j]);
        }
    }
    return lcs_max;
}

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

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

int q;
string X,Y;
int L[1000][1000];

int max(int i,int j) {return i > j ? i : j;}

int getL(int i,int j) {
	if(L[i][j] != -1) return L[i][j];

	if(i == 0 || j == 0) return 0;
	if(X[i - 1] == Y[j - 1]) return 1 + getL(i - 1,j - 1);
	return max(getL(i,j - 1),getL(i - 1,j));
}

int main() {

	cin >> q;
	for(int i = 0;i < q;i++) {
		for(int j = 0;j < 1000;j++) {
			for(int k = 0;k < 1000;k++) L[j][k] = -1;
		}
		cin >> X >> Y;
		cout << getL(X.size(),Y.size()) << endl;
	}
}

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

using namespace std;

int q;
int main() {
	cin >> q;
	for (int i = 0; i < q; i++) {
		string x, y;
		cin >> x >> y;
		int m = x.size();
		int n = y.size();
		x = ' ' + x;
		y = ' ' + y;
		int maxl = 0;
		int c[1001][1001] = {};
		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][j - 1], c[i - 1][j]);
				}
			}
		}
		cout << c[m][n] << endl;
	}
	return 0;
}

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


int main(int argc, char *argv[]){
  int n;
  cin >> n;
  for (int r = 0; r < n; r++) {

    string x, y;
    cin >> x >> y;
    int dp[y.length() + 1][x.length() + 1];
    memset(dp, 0, sizeof(dp));
    for (int i = 0; i < y.length(); i++) {
      for (int j = 0; j < x.length(); j++) {
        if(y[i] == x[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[y.length()][x.length()] << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define int long long
using ll=long long;
using vi=vector<int>;
using vl=vector<long long>;
using pii=pair<int,int>;
using pll=pair<long long,long long>;
#define ITR(i,c) for(auto i=begin(c);i!=end(c);++i)
#define FORE(x,c) for(auto &x:c)
#define REPF(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define REP(i,n) REPF(i,0,n)
#define REPR(i,n) for(int i=(int)(n);i>=0;--i)
#define REPW(i,n) for(i=0;i<(int)(n);++i)
#define ALL(c) begin(c),end(c)
#define RALL(c) rbegin(c),rend(c)
#define SZ(c) ((int)c.size())
#define CONTAIN(c,x) (c.find(x)!=end(c))
#define OUTOFRANGE(y,x,h,w) (y<0||x<0||y>=h||x>=w)
#define dump(...)
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
#define INF (1001001001)
#define INFLL (1001001001001001001ll)
template<class T> ostream& operator << (ostream &os,const vector<T> &v) {
    ITR(i,v) os << *i << (i==end(v)-1 ? "" : "\n"); return os; }
template<class T> istream& operator >> (istream &is,vector<T> &v) {
    ITR(i,v) is >> *i; return is; }
template<class T> istream& operator >> (istream &is, pair<T,T> &p) {
        is >> p.first >> p.second; return is; }
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
//------------------------------------------------------------------------------
struct before_main_function {
    before_main_function() {
        #ifdef int
            #undef INF
            #define INF INFLL
            #define stoi stoll
        #endif
        cin.tie(0);ios::sync_with_stdio(false);
        cout<<setprecision(15)<<fixed;
        #define endl "\n"
    }
} before_main_function;
//------------------8<------------------------------------8<--------------------

int lcs(string a,string b) {
    int n=a.size(),m=b.size();
    vector<vector<int>> dp(n+1,vector<int>(m+1,0));
    for(int i=0;i<n;i++) {
        for(int j=0;j<m;j++) {
            if(a[i]==b[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[n][m];
}
signed main() {
    int q;
    cin>>q;
    while(q--) {
        string x,y;
        cin>>x>>y;
        cout<<lcs(x,y)<<endl;
    }
    return 0;
}