Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	resolve()
}

func resolve() {
	n := scanInt(sc)
	results := []int{}
	for i := 0; i < n; i++ {
		results = append(results, resolveInstance())
	}
	for _, v := range results {
		fmt.Println(v)
	}
	return
}

func resolveInstance() int {
	x, y := scanString(sc), scanString(sc)
	lx, ly := len(x), len(y)
	dp := make([][]int, lx+1)
	dp[0] = make([]int, ly+1)
	for i := 1; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
		dp[i][0] = dp[i-1][0]
		for j := 1; j <= ly; j++ {
			dp[i][j] = dp[i-1][j]
			if dp[i][j] < dp[i][j-1] {
				dp[i][j] = dp[i][j-1]
			}
			if x[i-1] == y[j-1] {
				cL := dp[i-1][j-1] + 1
				if dp[i][j] < cL {
					dp[i][j] = cL
				}
			}
		}
	}
	return dp[lx][ly]
}

const (
	remove = 0 + iota
	match
)

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

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()

Python: def lcs_len(x, y):
    ly = len(y)
    tcsl = [0 for i in range(ly + 1)]
    for x_i in x:
        pre_tcsl = list(tcsl)
        for j in range(ly):
            if x_i == y[j]:
                tcsl[j] = pre_tcsl[j - 1] + 1
            else:
                tcsl[j] = max(pre_tcsl[j], tcsl[j - 1])
    print(tcsl[j])


q = int(input())

for i in range(q):
    ax = input()
    ay = input()
    lcs_len(ax, ay)

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: import sys

def LCS():
    str1=input()
    str2=input()

    l=len(str1)
    m=len(str2)
    x1=[0 for i in range(m+1)]
    for i in range(l):
        e1=str1[i]
        x2=x1+[]
        for j in range(m):
            if e1 == str2[j]:
                x1[j+1] = x2[j] + 1
            elif x1[j+1]<x1[j]:
                x1[j+1] = x1[j]
    return x1[-1]

n = int(input())
for i in range(n):
    
    print(LCS())

Python: import sys
e=sys.stdin.readline
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]
 print(len(z)-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))