Go: package main

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

type Position struct {
	X int
	Y int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}
	for i := 0; i < n; i++ {
		strX := nextText(sc)
		strY := nextText(sc)
		fmt.Println(calcLcs(strX, strY))
	}
}

func calcLcs(strX, strY string) int {
	return lcs(strX, strY, Position{0, 0}, make(map[Position]int))
}

func lcs(strX string, strY string, position Position, memo map[Position]int) int {
	if position.X >= len(strX) || position.Y >= len(strY) {
		return 0
	}
	if v, ok := memo[position]; ok {
		return v
	}
	if strX[position.X] == strY[position.Y] {
		result := lcs(strX, strY, Position{position.X + 1, position.Y + 1}, memo)
		memo[position] = result + 1
		return memo[position]
	} else {
		result1 := lcs(strX, strY, Position{position.X + 1, position.Y}, memo)
		result2 := lcs(strX, strY, Position{position.X, position.Y + 1}, memo)
		var result int
		if result1 > result2 {
			result = result1
		} else {
			result = result2
		}
		memo[position] = result
		return result
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
input:
3
abcbdab
bdcaba
abc
abc
abc
bc
"""
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] - 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(word_list[k], word_list[k + 1]))

Python: # -*- coding: utf-8 -*-
"""
http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_C

????????±?????¨??????
"""
import sys
from sys import stdin
input = stdin.readline


C = []
def calc_lcs4(X, Y):
    global C
    X = ' ' + X
    Y = ' ' + Y
    m = len(X)
    n = len(Y)

    C = [[0]*(n+1) for _ in range(m+1)] #  ???????????§??¨???

    max_lcs = 0

    pre_row = C[0]
    for i in range(1, m):
        row = C[i]
        XX = X[i]
        for j, YY in enumerate(Y):
            if XX == YY:
                pr_j1 = pre_row[j - 1]
                row[j] = pr_j1 + 1
                if pr_j1+1 > max_lcs:
                   max_lcs = pr_j1 + 1
            else:
                pr_j = pre_row[j]
                r_j1 = row[j-1]
                row[j] = max(pr_j, r_j1)
#                if pr_j >= r_j1:
#                    row[j] = pr_j
#                else:
#                    row[j] = r_j1
        pre_row = row

    print(max_lcs)


if __name__ == '__main__':
    num = int(input())

    for _ in range(num):
        X = input().strip()
        Y = input().strip()

        result = calc_lcs4(X, Y)

Python: import sys
from functools import lru_cache

# sys.setrecursionlimit(10 ** 5)

@lru_cache(maxsize=None)
def lcs_rec(i, j):
    if i == 0 or j == 0:
        return 0

    if X[i - 1] == Y[j - 1]:
        return lcs_rec(i - 1, j - 1) + 1
    else:
        return max(lcs_rec(i - 1, j), lcs_rec(i, j - 1))

def lcs_dp(m, n):
    for i in range(m + 1):
        for j in range(n + 1):
            if i == 0 or j == 0:
                dp[i][j] = 0
            elif X[i - 1] == Y[j - 1]:
                dp[i][j] = dp[i - 1][j - 1] + 1
            else:
                dp[i][j] = max(dp[i][j - 1], dp[i - 1][j])

dp = [[0] * (1000 + 1) for i in range(1000 + 1)]
q = int(input())

for i in range(q):
    X = input()
    Y = input()

    m = len(X)
    n = len(Y)

    lcs_dp(m, n)
    ans = dp[m][n]

    print(ans)

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+=f'\n{len(z)}'
print(a[1:])

Python: 
def LCS(x, y):
    len_x = len(x)
    len_y = len(y)
    
    dp = {}
    for i in range(len_x + 1):
        dp[i] = {0: 0}
    for j in range(len_y + 1):
        dp[0][j] = 0
    
    for i in range(1, len_x + 1):
        for j in range(1, len_y + 1):
            if x[i-1] == y[j-1]:
                dp[i][j] = dp[i-1][j-1] + 1
            else:
                dp[i][j] = max(dp[i][j-1], dp[i-1][j])
    
    return dp[len_x][len_y]

q = int(raw_input())
for i in range(q):
    X = raw_input()
    Y = raw_input()
    print(LCS(X, Y))

Python: q = int(input())


for __ in range (q):

    S1 = input()
    S2 = input()
    dp = [[0 for i in range(len(S2)+1+10)] for j in range(len(S1)+1+10)]


    for i in range (len(S1)):
        for j in range (len(S2)):
            if S1[i] == S2[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])

    print(dp[len(S1)][len(S2)])

Python: for _ in[0]*int(input()):
 X,z=input(),[]
 for y in input():
  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]
 print(len(z))

Python: q = int(input())
for _ in range(q):
    x = input()
    y = input()
    m = len(x)
    n = len(y)
    c = [0] * ((m + 1) * (n + 1))
    for i in range(1, m + 1):
        tmp = x[i - 1]
        for j in range(1, n + 1):
            if tmp == y[j - 1]:
                c[i * (n + 1) + j] = c[(i - 1) * (n + 1) + j - 1] + 1
            elif c[(i - 1) * (n + 1) + j] >= c[i * (n + 1) + j - 1]:
                c[i * (n + 1) + j] = c[(i - 1) * (n + 1) + j]
            else:
                c[i * (n + 1) + j] = c[i * (n + 1) + j - 1]
    print(c[m * (n + 1) + n])

Python: import sys

def lcm(c, i, j):
    if c[i][j]>=0: return c[i][j]
    if i==0 or j==0:
        c[i][j]=0
        return 0
    elif i>0 and j>0 and x[i-1]==y[j-1]:
        c[i][j] = lcm(c,i-1,j-1)+1
        return c[i][j]
    else:
        c[i][j] = max(lcm(c,i,j-1), lcm(c,i-1,j))
        return c[i][j]

for _ in range(int(sys.stdin.readline())):
    x = sys.stdin.readline()
    y = sys.stdin.readline()
    c = [[-1 for _ in range(len(y))] for _ in range(len(x))] 
    print(lcm(c,len(x)-1,len(y)-1))

Python: q = int(input())

for k in range(q):
    x = list(input())
    y = list(input())
    lcs = [0 for i in range(len(x)+1)] 
    for i in range(1,len(y) + 1):
        lcs_2 = [i for i in lcs]
        
        for j in range(1,len(x) + 1):
            if x[j-1] != y[i-1]:
                lcs[j] = max(lcs[j-1],lcs_2[j])
            else:
                lcs[j] = lcs_2[j-1] + 1
    print(lcs[len(x)])

Python: import sys

for _ in range(int(sys.stdin.readline())):
    x = sys.stdin.readline()
    y = sys.stdin.readline()
    c = [[0 for _ in range(len(y))] for _ in range(len(x))]
    

    for i in range(1,len(x)):
        for j in range(1,len(y)):
            if i>0 and j>0 and 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])
            
    print(c[len(x)-1][len(y)-1])

Python: def calc(x,y):
    n = len(x)
    m = len(y)
    dp1 = [0]*(m+1)
    for i in range(n):
        s = x[i]
        dp2 = dp1[:]
        for j in range(m):
            if s == y[j]:
                dp1[j+1] = dp2[j]+1
            elif dp1[j+1] < dp1[j]:
                dp1[j+1] = dp1[j]
    return dp1[-1]

q = int(input())
ans = []
for i in range(q):
    x = input()
    y = input()
    print(calc(x,y))