Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	Q := sc.nextInt()
	for q := 0; q < Q; q++ {
		X, Y := sc.nextStr(), sc.nextStr()
		xLen, yLen := len(X), len(Y)
		dp := make([][]int, xLen+1)
		for i := 0; i <= xLen; i++ {
			dp[i] = make([]int, yLen+1)
		}
		for x := 0; x <= xLen; x++ {
			for y := 0; y <= yLen; y++ {
				if x == 0 || y == 0 {
					dp[x][y] = 0
				} else if X[x-1] == Y[y-1] {
					dp[x][y] = dp[x-1][y-1] + 1
				} else {
					dp[x][y] = max(dp[x-1][y], dp[x][y-1])
				}
			}
		}
		fmt.Fprintln(wtr, dp[xLen][yLen])
	}

	wtr.Flush()
}

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

int LCS(string p, string q) {
	vector<vector<int> > f(p.size()+1, vector<int>(q.size()+1,0));
	int t;
	for (int i = 1; i <= p.size(); i++) {
		for (int j = 1; j <= q.size(); j++) {
			if (p[i-1] == q[j-1])
				f[i][j] = f[i - 1][j - 1] + 1;
			else if (f[i][j - 1] > f[i - 1][j])
				f[i][j] = f[i][j - 1];
			else
				f[i][j] = f[i - 1][j];
		}
	}
	return f[p.size()][q.size()];
}

int main() {
	int n;
	string p[150];
	cin >> n;
	for (int i = 0; i < n; i ++) {
		cin >> p[2*i] >> p[2*i + 1];
	}
	for (int i = 0; i < n; i++) {
		cout << LCS(p[2*i], p[2 * i + 1])<<endl;
	}
	return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
    using namespace std;
int lcs(string x,string y){
    int c[1010][1010];
    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=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(){
    int q;
    string x;
    string y;
    scanf("%d",&q);
    for (int i=0; i<q; i++) {
        cin>>x>>y;
        cout<<lcs(x, y)<<endl;
    }
    return 0;
}

C++: #include<iostream>
#include <cstdlib>
#include<list>
#include<stdio.h>
#include<algorithm>
#include<string>
#include<stack>
#define MAX 1001
using namespace std;
int main() {
	int n; cin >> n;
	string x, y; int data[MAX][MAX] = {0,0};
	for (int d = 0; d <n; d++)
	{
		cin >> x >> y;
		for (int i = 0; i < y.size(); i++)
		{
			for (int j = 0; j < x.size(); j++)
			{
				if (y[i] == x[j]) {
					data[j + 1][i + 1] = data[j][i] + 1;
				}
				else {
					data[j + 1][i + 1] = max(data[j + 1][i], data[j][i + 1]);
				}
			}
		}
		cout << data[x.size()][y.size()]<<endl;
	}
	
	return 0;
}

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

string s, t;
int dp[1001][1001];
int main()
{
    int p;
    cin >> p;
    while(p>0)
    {
        p--;
        cin >> s >> t;
        int n = s.size();
        int m = t.size();
        for (int i = 1; i <= n; i++)
            dp[i][0] = 0;
        for (int i = 1; i <= m; i++)
            dp[0][i] = 0;

        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                if (s[i - 1] == t[j - 1]) {
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                }
                else if (dp[i - 1][j] >= dp[i][j - 1]) {
                    dp[i][j] = dp[i - 1][j];
                }
                else {
                    dp[i][j] = dp[i][j - 1];
                }
            }
        }
        cout << dp[n][m] << endl;
    }

}

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

#define MAX 1024

int LCS[MAX][MAX];

int solve(string s1,string s2){
  if(s1.length() > s2.length())
	swap(s1,s2);
  for(int i=1;i<=s1.length();i++){
    for(int j=1;j<=s2.length();j++){
      if(s1[i-1]==s2[j-1])
	LCS[i][j]=LCS[i-1][j-1]+1;
      else
	LCS[i][j]=max(LCS[i][j-1],LCS[i-1][j]);
    }
  }
  return LCS[s1.length()][s2.length()];
}


int main(){
  string s1, s2;
  int n;
  cin >> n;
  for(int i=0;i<n;i++){
    for(int i=0;i<MAX;i++){
      for(int j=0;j<MAX;j++){
        LCS[i][j] = 0;
      }
    }
    cin>>s1>>s2;
    cout<<solve(s1,s2)<<endl;
    /*
    for(int i=0;i<=s1.length();i++){
      for(int j=0;j<=s2.length();j++){
	cout << LCS[i][j] << "  " ;
      }
      cout << endl;
    }*/
  }

}

C++: #include <iostream>
#include <vector>
#define eol '\n'
using namespace std;

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

  int q;
  cin >> q;
  for (int i = 0; i < q; i++) {
    string x,y;
    cin >> x >> y;

    int m,n;
    m = x.length();
    n = y.length();

    vector< vector<int> > mat(m+1, vector<int>(n+1,0));

    for (int sum = 2; sum <= m+n; sum++) {
      for (int j = 1; j <= min(sum-1,m); j++) {
        int k = sum - j;

        int plus = x[j-1] == y[k-1] ? 1 : 0;
        mat[j][k] = max(max(mat[j-1][k], mat[j][k-1]), mat[j-1][k-1] + plus);
      }
    }

    cout << mat[m][n] << eol;
  }
  
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
const long long INF = 123456789;
const long long MOD = 1000000007;
const long double PI = 3.1415926;
#define FOR(i, r, n) for (ll i = (ll)(r); i < (ll)(n); i++)
#define RFOR(i, r, n) for (ll i = (ll)(n - 1); i >= r; i--)
#define REP(i, n) FOR(i, 0, n)
#define RREP(i, n) RFOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
#define RALL(x) x.rbegin(), x.rend()
typedef long long int ll;
typedef vector<ll> vi;
typedef vector<pair<ll, ll> > vp;
typedef vector<string> vs;
typedef vector<char> vc;
typedef list<ll> lst;

ll n, m, k, ans = 0, sum = 0, cnt = 0;
string s;
char c;

#define Endl endl

/*--------------------template--------------------*/

int main()
{
    cin >> n;
    ll ma = 0;
    REP(i, n)
    {
        string t;
        cin >> s >> t;
        ll c[100][100] = { 0 };
        ma = 0;
        s = ' ' + s; //????????????????????????
        t = ' ' + t;
        FOR(i, 1, s.size())
        {
            c[i][0] = 0;
        }
        FOR(i, 1, t.size())
        {
            c[0][i] = 0;
        }
        FOR(i, 1, s.size())
        {
            FOR(j, 1, t.size())
            {
                if (s[i] == t[j]) {
                    c[i][j] = c[i - 1][j - 1] + 1;
                } else {
                    c[i][j] = max(c[i - 1][j], c[i][j - 1]);
                }
                ma = max(ma, c[i][j]);
            }
        }
        cout << ma << Endl;
    }
}