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

output:
4
3
2

"""
import sys


def lcs(A, B):
    m, n = len(A), len(B)
    count_list = [[0] * (n + 1) for _ in range(m + 1)]

    for i in range(1, m + 1):
        for j in range(1, n + 1):
            if A[i - 1] == B[j - 1]:
                count_list[i][j] = count_list[i - 1][j - 1] + 1
            elif count_list[i - 1][j] >= count_list[i][j - 1]:
                count_list[i][j] = count_list[i - 1][j]
            else:
                count_list[i][j] = count_list[i][j - 1]

    return count_list[m][n]


def lcs_better(A, B):
    costs = [0]
    for c in B:
        for index in range(len(costs) - 1, -1, -1):
            print(costs, index + 1)
            x_findex_index = A.find(c, costs[index])
            if x_findex_index != -1:
                if index + 1 < len(costs):
                    costs[index + 1] = min(costs[index + 1], x_findex_index + 1)
                else:
                    costs.append(x_findex_index + 1)
    return len(costs) - 1


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    pair_num = int(_input[0])

    word_list = _input[1:]
    # assert len(word_list) == 2 * pair_num
    for k in range(0, len(word_list), 2):
        print(lcs_better(word_list[k].strip(), word_list[k + 1].strip()))

Python: e=input
a=[]
for _ in[0]*int(e()):
 X,z=e(),[]
 for y in e():
  s=i=0
  for k in z:
   t=X.find(y,s)+1
   if t<1:break
   if t<k:z[i]=t
   s=k;i+=1
  else:
   t=X.find(y,s)+1
   if t:z+=[t]
 a+=[len(z)]
print('\n'.join(map(str,a)))

Python: from sys import stdin

X = [ 0 for i in range(1000) ]
Y = [ 0 for i in range(1000) ]
Z = [[0 for i in range(100)]for i in range(100)]

def getLCS(l) :
	xlen = len(X[l])
	ylen = len(Y[l])

	for i in range(1,xlen+1) :
		for j in range(1,ylen+1) :
			a = 1 if X[l][i-1] == Y[l][j-1] else 0
			Z[i][j] = max(Z[i-1][j-1] + a, Z[i-1][j], Z[i][j-1])

	return Z[xlen][ylen]

n = int(input())
for l in range(n) :
	X[l] = stdin.readline().strip()
	Y[l] = stdin.readline().strip()
	print(getLCS(l))

Python: n = int(input())
import sys

def input():
    return sys.stdin.readline().rstrip()
ans = []
def calc(s1,s2):
    lens1 = len(s1)
    lens2 = len(s2)
    # print(len(s1),s1[-1])
    dp = [0]*(lens2+1)
    for i in range(lens1):
        dp2 = dp[:]
        e = s1[i]
        for j in range(lens2):
            if e == s2[j]:
                dp[j+1] = dp2[j] + 1
            elif dp[j]>dp[j+1]:
                dp[j+1] = dp[j]
    # print(dp)
    ans.append(dp[-1])


for i in range(n):
    s1 = input()
    s2 = input()
    calc(s1,s2)
for i in ans:
    print(i)

# def lcs(x, y):
#     a = len(x)
#     b = len(y)
#     c1 = [0] * (b + 1)
#     for i in range(a):
#         e1 = x[i]
#         c2 = c1[:]
#         for j in range(b):
#             if e1 == y[j]:
#                 c1[j+1] = c2[j] + 1
#             elif c1[j+1] < c1[j]:
#                 c1[j+1] = c1[j]
#     return c1[-1]
    
# n = int(input().rstrip())
# ret = []
# for i in range(n):
#     s1 = input().rstrip()
#     s2 = input().rstrip()
#     ret.append(lcs(s1, s2))
# print(*ret, sep="\n")

Python: # -*- coding: utf-8 -*-
import sys
from itertools import product
sys.setrecursionlimit(100000)

N = int(input())

def calc_LCS(n, m):
    if n == 0 or m == 0:
        return 0
    elif X[n] == Y[m]:
        LCS[n][m] = LCS[n-1][m-1] + 1
        return LCS[n][m]
    else:
        LCS[n][m] = max(LCS[n-1][m], LCS[n][m-1])
        return LCS[n][m]
        

for _ in range(N):
    X = ["  "] + list(input())
    Y = [" "] + list(input())
    LCS = [[0 for _ in range(len(Y))] for _ in range(len(X))]
    max_ = 0
    for n, m in product(range(len(X)), range(len(Y))):
        max_ = max(max_, calc_LCS(n, m))
    print(max_)

Python: from collections import defaultdict


def longest_common_subsequence(s, t):
    dp = [[0] * (len(t) + 1) for _ in range(len(s) + 1)]
    for i in range(len(s)):
        for j in range(len(t)):
            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])
    return dp[-1][-1]


def longest_common_subsequence2(s, t):
    dp = [0] * (len(t) + 1)
    for i in range(len(s)):
        si = s[i]
        tmp = dp[:]
        for j in range(len(t)):
            if si == t[j]:
                dp[j + 1] = tmp[j] + 1
            elif dp[j + 1] < dp[j]:
                dp[j + 1] = dp[j]
    return dp[-1]


def main():
    n = int(input())
    for _ in range(n):
        X, Y = input(), input()
        print(longest_common_subsequence2(X, Y))


if __name__ == '__main__':
    main()