Go: package main

/*
最長共通部分列
*/

import (
	"bufio"
	"bytes"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func larger(l, r int) int {
	if l > r {
		return l
	}
	return r
}

var memo [1001][1001]int

func countLCS(x, y string) int {
	x = " " + x
	y = " " + y
	max := 0
	for xi := 1; xi < len(x); xi++ {
		for yi := 1; yi < len(y); yi++ {
			if x[xi] == y[yi] {
				memo[xi][yi] = memo[xi-1][yi-1] + 1
			} else {
				memo[xi][yi] = larger(memo[xi-1][yi], memo[xi][yi-1])
			}
			max = larger(max, memo[xi][yi])
		}
	}
	return max
}

func main() {
	scanner := makeScanner(1024)
	q := eGetInt(scanner)
	for i := 0; i < q; i++ {
		x := eGetLine(scanner)
		y := eGetLine(scanner)
		fmt.Println(countLCS(x, y))
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}
func min(a []int) int {
	m := a[0]
	for _, v := range a {
		if v < m {
			m = v
		}
	}
	return m
}

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <utility>
#include <numeric>
#include <array>
#include <cmath>
#include <memory>
using namespace std;
//変数デバッグ
#define DEB(variable) cout << #variable << '=' << variable << endl

//for簡易表記(引数ミス防止)
#define FOR(LoopVariable,numberOFbegin,numberOFend) for (int LoopVariable = (numberOFbegin); (LoopVariable) <= (numberOFend); (LoopVariable)++)
#define DEFOR(LoopVariable,numberOFbegin,numberOFend) for (int LoopVariable = (numberOFbegin)-1; (LoopVariable) >= (numberOFend); (LoopVariable)--)
#define REP(LoopVariable,numberOFend) for(int LoopVariable = 0;(LoopVariable)<(numberOFend);LoopVariable++)

constexpr long long int linf = numeric_limits<long long int>::max()-5;
constexpr int inf= numeric_limits<int>::max()-5;
constexpr long long int mod = 1000000007;


void solve(){
    string s, t;
    cin >> s >> t;
    vector<vector<int>> grid(s.size()+1, vector<int>(t.size()+1));

    grid[0][0] = 0;
    FOR(i,1,s.size()){
        grid[i][0] = 0;
    }
    FOR(i,1,t.size()){
        grid[0][i] = 0;
    }

    FOR(i,1,s.size()){
        FOR(j,1,t.size()){
            if(s[i-1]==t[j-1]){
                grid[i][j] = grid[i - 1][j - 1] + 1;
            }else{
                grid[i][j] = max(grid[i][j - 1], grid[i - 1][j]);
            }
        }

    }
    cout << grid[s.size()][t.size()] << endl;

}



int main(){

    int n;
    cin >> n;
    REP(i,n){
        solve();
    }

    return 0;
}

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

using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
typedef pair<ll, ll> Pll;
typedef vector<int> Vi;
typedef tuple<int, int, int> T;
#define FOR(i,s,x) for(int i=s;i<(int)(x);i++)
#define REP(i,x) FOR(i,0,x)
#define ALL(c) c.begin(), c.end()
#define DUMP( x ) cerr << #x << " = " << ( x ) << endl

int dp[1024][1024];

int main() {
  // use scanf in CodeForces!
  cin.tie(0);
  ios_base::sync_with_stdio(false);

  int N;
  cin >> N;
  REP(q, N) {
    memset(dp, 0, sizeof(dp));
    string X, Y;
    cin >> X >> Y;
    int LX = X.size(), LY = Y.size();
    REP(i, LX) REP(j, LY) {
      if (X[i] == Y[j]) {
	dp[i+1][j+1] = max(dp[i][j] + 1, max(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[LX][LY] << endl;
  }
  return 0;
}

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

#define rep(i, a, b) for (int i = a; i < (int)(b); ++i)
#define rrep(i, a, b) for (int i = b - 1; i >= (int)(a); --i)

using namespace std;

using ll = long long;
using vi = vector<int>;
using vii = vector<vi>;
using vll = vector<ll>;

int calc(vii& dp, const string& x, const string& y) {
    int m = x.size(), n = y.size();

    rep(i, 0, m) {
        rep(j, 0, n) {
            if (x[i] == y[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[m][n];
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int q;
    cin >> q;

    rep(i, 0, q) {
        string x, y;
        cin >> x >> y;

        vii dp(x.size() + 1, vi(y.size() + 1, 0));
        cout << calc(dp, x, y) << 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=1;i<=m;i++)c[i][0]=0;
  for(int i=1;i<=n;i++)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(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<iostream>
#include<string>

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

using namespace std;

int q;
string s, t;
int dp[151][151];

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cin >> q;
	rep(k, q) {
		cin >> s >> t;
		rep(i, 101) rep(j, 101) dp[i][j] = 0;
		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 + 1][j], dp[i][j + 1]);
				}
			}
		}
		cout << dp[s.size()][t.size()] << "\n";
	}
	return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;
int A[1005][1005]={};

int main() {
  int i,j,k,q;
  cin >> q;
  string a,b;
  for(i=0;i<q;i++) {
    cin  >> a >> b;
    int al = a.size();
    int bl = b.size();
    for(j=1;j<=al;j++) {
      for(k=1;k<=bl;k++) {
        if(a[j-1]==b[k-1]) {
          A[j][k]=A[j-1][k-1]+1;
        } else {
          A[j][k]=max(A[j][k-1],A[j-1][k]);
        }
      }
    }
    cout << A[al][bl] << endl;
  }
  return 0;
}