Go: package main

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

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func bordersInt(in_map [][]int, invalid int) [][]int{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]int, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]int, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func bordersString(in_map [][]string, invalid string) [][]string{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]string, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]string, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func maxInt(args... int) int{
	sort.Ints(args)
	return args[len(args)-1]
}

func main(){
	var n int 
	fmt.Scan(&n)
	dp := make([][]int, 1003)
	for i:=0; i<1003; i++ {
		dp[i] = make([]int, 1003)
	}
	input_lines := scanStringLine(2*n)
	for i:=0; i<n; i++ {
		S, T := input_lines[2*i], input_lines[2*i+1]
		lenS, lenT := len(S), len(T)
		for i:=1; i<lenS+1; i++ {
			for j:=1; j<lenT+1; j++ {
				if S[i-1] == T[j-1] {
					dp[i][j] = maxInt(dp[i-1][j-1]+1, dp[i-1][j], dp[i][j-1])
				} else {
					dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
				}
			}
		}
		fmt.Println(dp[lenS][lenT])
	}
}

C++: #if 0

#endif

#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;

int Q;
int L[1000+10][1000+10];

int main() {
  cin >> Q;
  string X, Y;
  for (int i = 0; i < Q; i++) {
    for (int j = 0; j < 1000+10; j++) {
      L[0][j] = 0; L[j][0] = 0;
    }
    cin >> X >> Y;
    for (int x = 1; x <= X.length(); x++) {
      for (int y = 1; y <= Y.length(); y++) {
        if (X[x-1] == Y[y-1])
          L[x][y] = L[x-1][y-1] + 1;
        else
          L[x][y] = max(L[x-1][y], L[x][y-1]);
      }
    }
    cout << L[X.length()][Y.length()] << endl;
  }
}

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

int main(){
  int n;
  char x[1001],y[1001];
  int dp[1002][1002];
  


  //load n;
  cin >>n;
  for(int i=0;i<n;i++){
    //initialize
    for(int i=0;i<1002;i++){
      for(int j=0;j<1002;j++){
	dp[i][j]=0; 
      }
    }
    //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++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
int main()
{
    int n;
    cin >> n;
    {
        string t;
        getline(cin, t);
    }
    for(int i=0;i<n;i++) {
        string s1, s2;
        getline(cin, s1);
        getline(cin, s2);
        vector<int> v1(s2.size()+1, 0);
        vector<int> v2(s2.size()+1, 0);
        for(auto c1=s1.cbegin(); c1!=s1.cend(); ++c1) {
            int i = 1;
            for(auto c2=s2.cbegin(); c2!=s2.cend(); ++c2,i++) {
                auto m = max(v1[i], v2[i-1]);
                m = max(m, v1[i-1] + (*c1 == *c2 ? 1 : 0));
                v2[i] = m;
            }
            /*
            for(auto t=v1.begin();t!=v1.end();++t) {
                cout << *t << " ";
            }
            cout << endl;
            */
            swap(v1, v2);
        }
        cout << v1[s2.size()] << endl;
    }
}

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

#define MAX_NUM 1001
int fLength;
int sLength;

int memo[MAX_NUM][MAX_NUM];
string f, s;

/*******************
  Longest Common Subsequence
  ??¨??????????????§??????????????????(??¨??????????????§?????????)
 *********************/

void solve() {
  for(int i = 0; i < fLength; i++) {
    for(int j = 0; j < sLength; j++) {
      if(f[i] == s[j]) {
        memo[i + 1][j + 1] = memo[i][j] + 1;
      }
      else {
        memo[i + 1][j + 1] = max(memo[i + 1][j], memo[i][j + 1]);
      }
    }  
  }
}


int main(void) {
  int n;
  cin >> n;


  //?????????
  memset(memo, 0, sizeof(memo));
  for(int i = 0; i < n; i++) {
    cin >> f >> s;
    fLength = f.size();
    sLength = s.size();
    solve();
    cout << memo[fLength][sLength] << endl;
  }
  return 0;
}

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

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

template<class T> inline T sqr(T x) {return x*x;}

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> P;
typedef long long ll;

#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())
#define REVERSE(c) reverse((c).begin(),(c).end())

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

const double EPS = 1e-10;
const double PI  = acos(-1.0);
const long long INF = 1000000007;

#define CLR(a) memset((a), 0 ,sizeof(a))

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

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

int main(void){
    int q; cin >> q;
    VS X(q), Y(q); REP(i,q) cin >> X[i] >> Y[i];

    REP(k,q){
        int dp[X[k].size()+1][Y[k].size()+1]; REP(i,X[k].size()+1)REP(j,Y[k].size()+1) dp[i][j] = 0;
        REP(i,X[k].size())REP(j,Y[k].size()){
            if(X[k][i] == Y[k][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]);
        }
        cout << dp[X[k].size()][Y[k].size()] << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
#define MAX_SEQ 1000

int main() {
  int n; cin >> n;

  for(int i=0;i<n;i++) {
    char seq1[MAX_SEQ+1];
    char seq2[MAX_SEQ+1];
    vector<char> seq_sub;
    cin >> seq1;
    cin >> seq2;
    int seq1_len = 0;
    int seq2_len = 0;
    while(seq1[seq1_len] != '\0')
      seq1_len++;
    while(seq2[seq2_len] != '\0')
      seq2_len++;

    /*
    cout << "length" << endl;
    cout << seq1_len << endl;
    cout << seq2_len << endl;
    */

    int lcs[seq1_len+1][seq2_len+1];
    for(int i=0;i<=seq1_len;i++)
      lcs[i][0] = 0;
    for(int i=0;i<=seq2_len;i++)
      lcs[0][i] = 0;

    for(int i=1;i<=seq1_len;i++) {
      for(int j=1;j<=seq2_len;j++) {
        int s1_it = i-1;
        int s2_it = j-1;
        if(seq1[s1_it] == seq2[s2_it]) {
          lcs[i][j] = lcs[i-1][j-1] + 1;
        }
        else {
          lcs[i][j] = max(lcs[i][j-1],lcs[i-1][j]);
        }
      }
    }
    /*
    cout << "lcs[i][j]" << endl;
    for(int i=0;i<=seq1_len;i++) {
      for(int j=0;j<=seq2_len;j++) {
        cout << lcs[i][j] << " ";
      }
      cout << endl;
    }
    */

    cout << lcs[seq1_len][seq2_len] << endl;
  }
}