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
}

Python: def len_lcs(s1, s2):
    """Find length of the longest common sequence(LCS) of strings s1 and s2.

    >>> len_lcs("abc", "abc")
    3
    >>> len_lcs("abcbdaba", "bdcaba")
    5
    """
    def match(c1, c2):
        if c1 == c2:
            return 1
        else:
            return 0

    if len(s1) == 0 or len(s2) == 0:
        return 0

    primary = [0] * len(s1)
    secondary = [0] * len(s1)

    for i in range(len(s2)):
        for j in range(len(s1)):
            if j == 0:
                secondary[j] = max(primary[j], match(s1[j], s2[i]))
            else:
                secondary[j] = max(secondary[j-1], primary[j],
                                   primary[j-1] + match(s1[j], s2[i]))

        primary, secondary = secondary, primary

    return primary[len(s1)-1]


def run():
    n = int(input())

    for _ in range(n):
        s1 = input()
        s2 = input()
        print(len_lcs(s1, s2))


if __name__ == '__main__':
    run()

Python: import sys
q = int(sys.stdin.readline().strip())
for _ in range(q):
    x = sys.stdin.readline().strip()
    y = sys.stdin.readline().strip()
    n = len(x)
    m = len(y)
    dp = [0 for j in range(m + 1)]

    for i in range(1, n + 1):
        dp_prev = dp[:]
        for j in range(1, m + 1):
            if x[i - 1] == y[j - 1]:
                dp[j] = dp_prev[j - 1] + 1
            elif dp_prev[j] < dp[j - 1]:
                dp[j] = dp[j - 1]
                
    print(dp[m])

Python: def gen_dp(row, col):
  return [[0]*col for i in range(row)]

def solver(str_1 ,str_2):
  dp = gen_dp(len(str_2) + 1, len(str_1) + 1)
  for r in range(len(str_2)):
    for c in range(len(str_1)):
      if str_2[r] == str_1[c]:
        dp[r + 1][c + 1] = dp[r][c] + 1
      else:
        dp[r + 1][c + 1] = max(dp[r + 1][c], dp[r][c + 1])
  return dp[len(str_2)][len(str_1)]

n = int(input())
for _ in range(n):
  str_1 = input()
  str_2 = input()
  print(solver(str_1, str_2))

Python: import sys


n = int(input())

def calc(data1, data2):
    term = len(data1)+1
    table = [0]*term

    for i, d2 in enumerate(data2):
        tmp_table = table[:]
        for j, d1 in enumerate(data1):
            if d1 == d2:
                table[j + 1] = tmp_table[j] + 1
            elif table[j+1] < table[j]:
                table[j + 1] = table[j]

    print(table[term-1])
    return 

for _ in range(n):
    data1 = sys.stdin.readline().rstrip()
    data2 = sys.stdin.readline().rstrip()
    calc(data1, data2)

Python: def lcs_fast(x, y):
    len_x = len(x)
    len_y = len(y)

    c = [0] * (len_y + 1)
    for i in range(len_x):
        c_prev = c[:]
        for j in range(len_y):
            if x[i] == y[j]:
                c[j+1] = c_prev[j] + 1
            elif c[j+1] < c[j]:
                c[j+1] = c[j]
    return c[-1]


if __name__ == "__main__":
    n = int(input())
    for i in range(n):
        x = input()
        y = input()
        # print(lcs(x, y))
        print(lcs_fast(x, y))

C++: #include <iostream>
#include <cstring>
#include <cstdlib>
#include <sstream>
#include <stack>
#include <queue>
#include <list>
#include <stdio.h>
#include <algorithm>
#define MAX 100000
using namespace std;
typedef long long ll;
int dp[1002][1002];
int lcs(string a,string b)
{
	a=" "+a;
	b=" "+b;
	int m,n;
	m=a.size();
	n=b.size();
	
	for(int i=1;i<=m;i++){
		for(int j=1;j<=n;j++){
			if(a[i]==b[j]){
				dp[i][j]=dp[i-1][j-1]+1;
			}else{
				dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
			}
		}
	}
	return dp[m][n]-1;
}
int main()
{	
	int n;
	string a,b;
	cin>>n;
	for(int i=0;i<n;i++)
	{
		cin>>a>>b;
		cout<<lcs(a,b)<<endl;
	}
	return 0;
}

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

using namespace std;

int lcs(const string & a, const string & b)
{
    vector<vector<int> > dp(a.size(), vector<int>(b.size()));

    for (size_t i = 0; i < dp.size(); ++i) {
        for (size_t j = 0; j < dp[0].size(); ++j) {
            if (a.at(i) == b.at(j)) {
                dp[i][j] = ((i == 0 || j == 0) ? 0 : dp[i - 1][j - 1]) + 1;
            } else {
                dp[i][j] = max(i == 0 ? 0 : dp[i - 1][j],
                               j == 0 ? 0 : dp[i][j - 1]);
            }
        }
    }

    return dp[a.length() - 1][b.length() - 1];
}

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

    return 0;
}

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

#define MAX_NUM 100
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;
}