Go: package main

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

var (
	nstr   func() string
	stdout *bufio.Writer
)

func init() {
	nstr = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func main() {
	defer stdout.Flush()

	n := nint()
	xList := make([]string, n)
	yList := make([]string, n)

	for i:=0;i<n ;i++  {
		xList[i] = nstr()
		yList[i] = nstr()
	}

	for i := 0; i<n	; i++  {
		fmt.Println(lcs(xList[i], yList[i]))
	}

}

func lcs(x string, y string) int{
	var m = len(x)
	var n = len(y)

	c := make([][]int, m+1)
	for i:= range c{
		c[i] = make([]int, n+1)
	}
	for i:=	1;i<=m ;i++  {
		for j:=1;j<=n ;j++  {
			if x[i-1] == y[j-1]{
				c[i][j] = c[i-1][j-1] + 1
			}else{
				c[i][j] = int(math.Max(float64(c[i-1][j]), float64(c[i][j-1])))
			}


		}
	}
	return c[m][n]

}


func newReadString(ior io.Reader) func() string {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), int(1e+11))
	r.Split(bufio.ScanWords)

	return func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
}

func nint64() int64 {
	i, err := strconv.ParseInt(nstr(), 0, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func nint() int {
	return int(nint64())
}

func getIntSlice(n int) []int {
	b := make([]int, n)
	for i := 0; i < n; i++ {
		b[i] = nint()
	}
	return b
}

func getStringSlice(n int) []string {
	b := make([]string, n)
	for i := 0; i < n; i++ {
		b[i] = nstr()
	}
	return b
}

func gcd(x, y int) int {
	if y == 0 {
		return x
	}
	return gcd(y, x%y)
}

func lcm(x, y int) int {
	return x * y / gcd(x, y)
}

func contains(s []int, e int) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func bin(i int, prefix bool) string {
	i64 := int64(i)

	if prefix {
		return "0b" + strconv.FormatInt(i64, 2)
	} else {
		return strconv.FormatInt(i64, 2)
	}
}

func strReverse(s string) string {
	runes := []rune(s)
	for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
		runes[i], runes[j] = runes[j], runes[i]
	}

	return string(runes)
}

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

int main(){
  int n;
  char x[1001],y[1001];
  int dp[1010][1010];
  
  //load n;
  cin >>n;
  for(int i=0;i<n;i++){
    //load string
    scanf("%s",x);
    scanf("%s",y);
    //dp
    for(int j=0;j<strlen(x);j++){
      for(int k=0;k<strlen(y);k++){
	if(x[j]==y[k]){
	  dp[j+1][k+1]=dp[j][k]+1;
	}

	else{
	  if(dp[j][k+1]>dp[j+1][k]){
	    dp[j+1][k+1]=dp[j][k+1];
	  }

	  else{
	    dp[j+1][k+1]=dp[j+1][k];
	  }


	}
      }
    }

    //print
    cout <<dp[strlen(x)][strlen(y)]<<endl;
  }



  return 0;
}

C++: // http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_C
#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>

#define debug(x) cout << #x << "==" << x << endl;

using namespace std;

//??\???
#define MAX_LEN 1000
int N;
int dp[MAX_LEN + 1][MAX_LEN + 1];

void print_dp_table(int n, int m) {
  for(int i = 0; i < n; i++) {
    for(int j = 0; j < m; j++) {
      cout <<setw(2) << dp[i][j];
    }
    cout << "\n";
  }
  cout << "\n";
}

int main() {
  ios::sync_with_stdio(false);

  cin >> N;

  string s1, s2;

  while( cin >> s1 >> s2 ) {

    std::vector<char> a;
    std::vector<char> b;
    for(char& c : s1) {
      a.push_back(c);
    }
    for(char& c : s2) {
      b.push_back(c);
    }


    // dp[i][j] := a???i???????????§???b???j???????????§????????¨??????????????±?????¨??????
    // dp ????????????????????????
    fill(dp[0], dp[MAX_LEN + 1], 0);

    for(int i = 1; i <= (int)a.size(); i++ ) {
      for(int j = 1; j <= (int)b.size(); j++) {
        if( a[i-1] == b[j-1] ) {
          dp[i][j] = dp[i-1][j-1] + 1;
        } else {
          dp[i][j] = max( dp[i-1][j], dp[i][j-1] );
        }
      }
    }

    // for( int i = 0; i < (int)a.size(); i++) {
    //   for( int j = 0; j < (int)b.size(); j++) {
    //     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_table(a.size(), b.size());
    cout << dp[a.size()][b.size()] << endl;

  }

  return 0;
}

C++: #include <bits/stdc++.h>

#define REP(i, n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()
const int INF = 1e9;

using namespace std;
int dp[1005][1005];

int main() {
    int n; cin >> n;
    REP(k, n){
        REP(i, 1005) REP(j, 1005) dp[i][j] = 0;
        string a, b;
        cin >> a >> b;
        REP(i, a.length()){
            string q = a.substr(i, 1);
            REP(j, b.length()){
                string t = b.substr(j, 1);
                if(q == t){
                    if(i == 0 || j == 0)
                        dp[i][j] = 1;
                    else
                        dp[i][j] = max(dp[i-1][j], dp[i][j-1] + 1);
                }
                if (i != 0 && j != 0)
                    dp[i][j] = (dp[i-1][j] > dp[i][j-1]) ? max(dp[i][j], dp[i-1][j]) : max(dp[i][j], dp[i][j-1]);
                else if (i != 0)
                    dp[i][j] = max(dp[i][j], dp[i-1][j]);
                else if (j != 0)
                    dp[i][j] = max(dp[i][j], dp[i][j-1]);
            }
        }
        cout << dp[a.length()-1][b.length()-1] << endl;
    }
    return 0;
}

C++: #include <algorithm>
#include <cmath>
#include <cstdio>
#include <iostream>
#include <numeric>
#include <queue>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int f(string &x, string &y, int xi, int yi, vector<vector<int>> &memo) {
    if (xi < 0 || yi < 0) return 0;
    if (memo[xi][yi] != -1) return memo[xi][yi];
    int ret;
    if (x[xi] == y[yi])
        ret = f(x, y, xi - 1, yi - 1, memo) + 1;
    else
        ret = max(f(x, y, xi - 1, yi, memo), f(x, y, xi, yi - 1, memo));
    memo[xi][yi] = ret;
    return ret;
}

int main() {
    int q;
    cin >> q;
    for (; q; --q) {
        string x, y;
        cin >> x >> y;
        int xl = x.size(), yl = y.size();
        vector<vector<int>> memo(xl, vector<int>(yl, -1));
        cout << f(x, y, xl - 1, yl - 1, memo) << endl;
    }
    return 0;
}

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

#define rep(i,n) for(int i=0;i<(n);i++)

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

using namespace std;

int dp[1003][1003];
int main() {
    int q; cin>>q;
    rep(_,q) {
        string s,t;
        cin>>s>>t;
        s=" "+s;
        t=" "+t;
        rep(i,s.size()) rep(j,s.size()) if(i&&j) {
            if(s[i]==t[j]) dp[i][j]=dp[i-1][j-1]+1;
            else {
                chmax(dp[i][j],dp[i-1][j]);
                chmax(dp[i][j],dp[i][j-1]);
            }
        }
        int ans=0;
        rep(i,s.size()) chmax(ans,*max_element(dp[i],dp[i]+t.size()));
        cout<<ans<<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 ;
    for (int i = 0; i <= m; i++) c[i][0] = 0;
    for (int j = 0; 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][j-1], c[i-1][j]) ;
            }
            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 ;
}