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<bits/stdc++.h>
using namespace std;
#define rp(i,j) for(long long i=0;i<j;i++)
#define rep(i,j,k) for(long long i=j;i<k;i++)
#define mod 1000000007
#define NIL -1
typedef long long ll;
int lcs(string x,string y){
    int dp[1001][1001];
    int maxl=0;
    int X=x.size(),Y=y.size();
    x=" "+x;y=" "+y;
    rp(j,X+1)dp[j][0]=0;
    rp(j,Y+1)dp[0][j]=0;
    rep(j,1,X+1){
        rep(k,1,Y+1){
            if(x[j]==y[k])dp[j][k]=dp[j-1][k-1]+1;
            else dp[j][k]=max(dp[j-1][k],dp[j][k-1]);
        }
    }
    return dp[X][Y];
}
int main(){
    int q;cin>>q;
    rp(i,q){
        string s1,s2;
        cin>>s1>>s2;
        cout<<lcs(s1,s2)<<endl;
    }
}

C++: #include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <list>
#include <queue>
#include <deque>
#include <algorithm>
#include <numeric>
#include <utility>
#include <complex>
#include <functional>
#include <climits>

using namespace std;


int lcs(string x, string y) {
    int c[1001][1001];
    int n = x.length();
    int m = y.length();
    for(int i = 0; i < n; i++) {
        c[i][0] = 0;
    }
    for(int j = 0; j < m; j++) {
        c[0][j] = 0;
    }
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; j++) {
            if(x[i-1] == y[j-1]) {
                c[i][j] = c[i-1][j-1] + 1;
            } else {
                c[i][j] = max(c[i][j-1], c[i-1][j]);
            }
        }
    }
    return c[n][m];
}

int main() {
    int n;
    cin >> n;
    for(int i=0; i<n; i++) {
        string s1, s2;
        cin >> s1 >> s2;
        cout << lcs(s1, s2) << endl;
    }
}

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

std::string x,y;
int lcs[1000][1000];

int max(int k,int l){
  if(k>l){
    return k;
  }else{
    return l;
  }
}

void LCS(int i,int j){
  if(x[i] == y[j]){
    lcs[i][j] = lcs[i-1][j-1]+1;
  }else{
    lcs[i][j] = max(lcs[i-1][j],lcs[i][j-1]);
  }
}

void pre(){
  for(int i=0;i<(int)y.size();i++){
    if(x[0] == y[i]){
      for(int j=i;j<(int)y.size();j++){
	lcs[0][j] = 1;
      }
      break;
    }else{
      lcs[0][i] = 0;
    }
  }

  for(int i=0;i<(int)x.size();i++){
    if(x[i] == y[0]){
      for(int j=i;j<(int)x.size();j++){
	lcs[j][0] = 1;
      }
      break;
    }else{
      lcs[i][0] = 0;
    }
  }

}

int main(){
  int q;
  std::cin >> q;
  for(int k=0;k<q;k++){
    std::cin >> x;
    std::cin >> y;
    int size_x=x.size(),size_y=y.size();
    pre();
    for(int i=1;i<size_x;i++){
      for(int j=1;j<size_y;j++){
	LCS(i,j);
      }
    }

    /*for(int i=0;i<size_x;i++){
      for(int j=0;j<size_y;j++){
	std::cout << lcs[i][j] << ' ';
      }
      std::cout << '\n';
    }
    */
    
    std::cout << lcs[size_x-1][size_y-1] << '\n'; 

  }
  return 0;
}

C++: #include <algorithm>
#include <iostream>
#include <string>
using namespace std;
#define MAX 1000


int solve(string x, string y) {
  int lcs[MAX + 1][MAX + 1];
  int xl = x.size();
  int yl = y.size();

  int i, j;
  for (i = 0; i < xl; i++)
    lcs[i][0] = 0;
  for (j = 0; i < yl; j++)
    lcs[0][j] = 0;

  // shift
  x = " " + x;
  y = " " + y;

  int maxlcs = 0;
  for (i = 1; i <= xl; i++) {
    for (j = 1; j <= yl; j++) {
      if (x[i] == y[j]) {
        lcs[i][j] = lcs[i - 1][j - 1] + 1;
      } else {
        int a = lcs[i][j - 1];
        int b = lcs[i - 1][j];
        lcs[i][j] = max(a, b);
      }
      maxlcs = max(maxlcs, lcs[i][j]);
    }
  }
  return maxlcs;
}

int main() {
  string s1, s2;
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> s1;
    cin >> s2;
    cout << solve(s1, s2) << endl;
  }
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <string>
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>

using namespace std;

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

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

// ---------------------
#define INF 922337203685477580
typedef long long ll;

int dp[1000][1000];

int main() {
  int q;
  cin >> q;
  REP(loop, q) {
    char S[1000], T[1000];
    cin >> S >> T;

    REP(i, strlen(S)) {
      REP(j, strlen(T)) {
        dp[i][j] = 0;
      }
    }
    for (int i = 0; i < strlen(S); i++) {
      for (int j = 0; j < strlen(T); j++) {
        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[strlen(S)][strlen(T)] << endl;
  }

  return 0;
}