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(){
	buf := make([]byte, 0)
    sc.Buffer(buf, 1000000009)
	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])
	}
}

Python: def Ics(X, Y):
    m = len(X)
    n = len(Y)
    maxl = 0
    for i in range(m + 1):
        c[i][0] = 0
    for j in range(1, n + 1):
        c[0][j] = 0
    for i in range(1, m + 1):
        for j in range(1, n + 1):
            if(X[i] == Y[j]):
                c[i][j] = c[i - 1][j - 1] + 1
            else:
                c[i][j] = max(c[i][j - 1], c[i - 1][j])
            maxl = max(maxl, c[i][j])
    return maxl

q = int(input().rstrip())
t = []
for i in range(n):
    s1 = input().rstrip()
    s2 = input().rstrip()
    t.append(lcs(s1, s2))
print(*t, sep="\n")

Python: def calc(x,y):
    i = len(x)
    j = len(y)
    if d[i][j]:
        return d[i][j]
    else:
        if i == 1:
            if x in y:
                d[i][j] = 1
                return 1
            else:
                d[i][j] = 0
                return 0
        elif j == 1:
            if y in x:
                d[i][j] = 1
                return 1
            else:
                d[i][j] = 0
                return 0
        else:
            if x[-1] == y[-1]:
                tmp = max(calc(x[:-1],y[:-1])+1,calc(x[:-1],y),calc(x,y[:-1]))
                d[i][j] = tmp
                return tmp
            else:
                tmp = max(calc(x[:-1],y),calc(x,y[:-1]))
                d[i][j] = tmp
                return tmp
        
q = int(input())
for i in range(q):
    x = input()
    y = input()
    d = [[None for _ in range(len(y)+1)] for _ in range(len(x)+1)]
    print(calc(x,y))

Python: def search(X, Y):
    dp = [[0] * (len(Y)+1) for x in range(len(X)+1)]
    for x in range(1, len(X) + 1):
        for y in range(1, len(Y) + 1):
            if X[x-1] == Y[y-1]:
                dp[x][y] = dp[x-1][y-1] + 1
            elif dp[x-1][y] > dp[x][y-1]:
                dp[x][y] = dp[x-1][y]
            else:
                dp[x][y] = dp[x][y-1]
    return dp[-1][-1]

for _ in range(int(input())):
    X = input()
    Y = input()
    print(search(X, Y))

Python: n = int(input())

# result = []

memo = {}


def search(s1, s2):

    if (s1, s2) in memo:
        return memo[(s1, s2)]

    total = [0]

    if s1:
        s1_head, s1_body = s1[0], s1[1:]
        for idx2, s2_tgt in enumerate(s2):
            if s1_head == s2_tgt:
                total.append(1+search(s1_body, s2[idx2+1:]))

    if s2:
        s2_head, s2_body = s2[0], s2[1:]
        for idx1, s1_tgt in enumerate(s1):
            if s2_head == s1_tgt:
                total.append(1+search(s1[idx1+1:], s2_body))

    if s1 and s2:
        total.append(search(s1[1:], s2[1:]))

    memo[(s1, s2)] = max(total)
    return max(total)
    # print(rs)


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

Python: import bisect


def LCS(S, T):
    N = len(S)
    M = len(T)
    dp = [[0] * (M + 1) for _ in range(N + 1)]

    for i, s in enumerate(S, start=1):
        for j, t in enumerate(T, start=1):
            if s == t:
                dp[i][j] = dp[i - 1][j - 1] + 1
            else:
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1])
    return dp[N][M]


def LCS_HTKB(S, T):
    T = T[::-1]
    memo = []

    for s in S:
        i = T.find(s) + 1
        while i:
            j = bisect.bisect_left(memo, -i)
            if j >= len(memo):
                memo.append(-i)
            else:
                memo[j] = -i
            i = T.find(s, i) + 1
    return len(memo)


if __name__ == "__main__":
    Q = int(input())
    ans = []
    for _ in range(Q):
        ans.append(LCS_HTKB(input(), input()))
    print(*ans, sep="\n")

Python: def lcs(X, Y):
    global c
    m, n = len(X), len(Y)
    c = [[0 for i in range(n+1)] for j in range(m+1)]
    for i in range(1, m+1):
        for j in range(1, n+1):
            if X[i-1] == Y[j-1]:
                c[i][j] = c[i-1][j-1] + 1
            else:
                c[i][j] = max(c[i-1][j], c[i][j-1])
    return c[m][n]

def lcs_improved(X, Y):
    hist = [0] # yの文字cまでを見た時に, hist[i]以降の文字列において, 共通文字のうち, 一番小さいindexのもの
    for c in Y:
        for i in range(len(hist)-1, -1, -1):
            next_match_i = X.find(c, hist[i])+1
            if next_match_i:
                if i+1 < len(hist):
                    hist[i+1] = min(hist[i+1], next_match_i)
                else:
                    hist.append(next_match_i)
    return len(hist)-1

q = int(input())
for i in range(q):
    X = input()
    Y = input()
    print(lcs_improved(X, Y))

Python: #!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
input:
3
abcbdab
bdcaba
abc
abc
abc
bc

output:
4
3
2

"""
import sys


def lcs(w1, w2):
    m, n = len(w1), len(w2)
    dp = [[0] * (n + 1) for _ in range(m + 1)]
    max_l = 0
    for i in range(1, m + 1):
        for j in range(1, n + 1):
            if w1[i - 1] == w2[j - 1]:
                dp[i][j] = dp[i - 1][j - 1] + 1
            else:
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1])
            max_l = max(max_l, dp[i][j])

    return max_l


def solve():
    input_ = sys.stdin.readlines()
    pair_num = int(input_[0])

    word_list = input_[1:]
    # assert len(word_list) == 2 * pair_num

    for pair in zip(word_list[::2], word_list[1::2]):
        cw1, cw2 = map(lambda x: x.strip(), pair)
        print(lcs(cw1, cw2))
        # l1, l2 = len(cw1), len(cw2)
        # print(lcs_recursive(cw1, cw2, l1, l2))

    return


if __name__ == '__main__':
    solve()

Python: def lcs(s1, s2):
    n, m = len(s1), len(s2)
    dp = [[0] * (m+1) for _ in range(n+1)]

    for i in range(1, n+1):
        for j in range(1, m+1):
            if s1[i-1] == s2[j-1]:
                dp[i][j] = dp[i-1][j-1] + 1
            else:
                dp[i][j] = max(dp[i-1][j], dp[i][j-1])

    return dp[n][m]

def solve():
    N = int(input())
    for _ in range(N):
        a = input()
        b = input()
        print(lcs(a, b))

if __name__ == '__main__':
    solve()