Go: package main

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

func max(x, y int) int {
	if x < y {
		return y
	} else {
		return x
	}
}

/*********************************************************************
長さmの列X_(m)と長さnの列Y_(n)の最長共通部分列LCSは、
	(1)X[m] == Y[n]ならば、X_(m-1)とY_(n-1)のLCSにX[m]を繋げたもの
	(2)X[m] != Y[n]ならば、X_(m-1)とY_(n)のLCSもしくはX_(m)とY_(n-1)のLCS
	のいずれかのうち長い方

c[m+1][n+1]：c[i][j]にX_(i)とY_(j)のLCSの長さを格納する二次元配列
*********************************************************************/

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Scan()
	n, _ := strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		scanner.Scan()
		s1 := scanner.Text()
		scanner.Scan()
		s2 := scanner.Text()
		s1, s2 = " " + s1 , " " + s2
		c := make([][]int, len(s1))
		for i := range c {
			c[i] = make([]int, len(s2))
		}

		LCS := 0

		for i := 1; i < len(s1); i++ {
			for j := 1; j < len(s2); j++ {
				if s1[i] == s2[j] {
					c[i][j] = c[i-1][j-1] + 1
				} else {
					c[i][j] = max(c[i-1][j], c[i][j-1])
				}
				LCS = max(LCS, c[i][j])
			}
		}
		fmt.Println(LCS)
	}
}

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

最長共通部分列
"""


c = []
def prep_array(X, Y):
    global c
    """ 値が0の2次元配列を用意する。サイズは入力データの最大値を想定して縦横(1000+1)以上必要。 """
    # from array import array
    # c = [array('I', [0] * (len(X)+1)) for _ in range(len(Y)+1)]  #  arrayで用意
    c = [[0]*(len(Y)+2) for _ in range(len(X)+2)] #  リストで用意
    return c


def check_max(array):
    """ 2次元配列の中の最大の値を返す """
    max_lcs = 0
    for row in array:
        temp_max = max(row)
        if temp_max > max_lcs:
            max_lcs = temp_max
    return max_lcs


def calc_lcs4(X, Y, c):
    """
    Y[j]のアクセス方法を変更
    リストの値を一旦変数に保存するように変更
    最長共通部分長を関数内で計算するように変更
    4/5 のテストデータを使用してプロファイリングすると実効時間は 5.6秒
    """
    X = ' ' + X
    Y = ' ' + Y
    m = len(X)
    n = len(Y)
    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]
                if pr_j >= r_j1:
                    row[j] = pr_j
                else:
                    row[j] = r_j1
        pre_row = row
    return max_lcs


if __name__ == '__main__':
    # データの入力
    num = int(input())
    #f = open('input.txt')
    #num = int(f.readline())

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

        # 処理の実行
        result = calc_lcs4(X, Y, prep_array(X, Y))

        # 結果の表示
        print(result)

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: from sys import stdin

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


def getLCS() :
	xlen = len(X[l])
	ylen = len(Y[l])
	Z = [[0 for i in range(xlen+2)]for i in range(ylen+2)]


	for i in range(1,xlen+1) :
		for j in range(1,ylen+1) :
			if X[i-1] == Y[j-1] : Z[i][j] = Z[i-1][j-1] + 1
			elif Z[i-1][j] >= Z[i][j-1] : Z[i][j] = Z[i-1][j]
			else : Z[i][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())

Python: import sys


def lcs(X, Y):
    m = len(X)
    n = len(Y)
    c = [[0] * (n+1) if i == 0 else [0] + [None] * n for i 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
            elif c[i-1][j] >= c[i][j-1]:
                c[i][j] = c[i-1][j]
            else:
                c[i][j] = c[i][j-1]
    return c[m][n]


if __name__ == "__main__":
    n = int(sys.stdin.readline())
    inp = sys.stdin.readlines()
    for i in range(n):
        print(lcs(inp[2*i][:-1], inp[2*i+1][:-1]))

Python: def main(X, Y):
    M = len(Y)
    dp = [0]*(M+1)
    for i, x in enumerate(X):
        dp_pre = dp[:]
        for j, y in enumerate(Y):
            if x == y:
                dp[j+1] = dp_pre[j] + 1
            elif dp[j+1] < dp[j]:
                dp[j+1] = dp[j]
    return print(dp[M])


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

Python: def lcs(X,Y,p,q,Z):
    for i in range(p):
        for j in range(q):
            if X[i]==Y[j]:
                Z[i+1][j+1]=Z[i][j]+1
            else:
                if Z[i][j+1]>Z[i+1][j]:
                    Z[i+1][j+1]=Z[i][j+1]
                else:
                    Z[i+1][j+1]=Z[i+1][j]
    print(Z[p][q])

n=int(input())
for i in range(n):
    X=input()
    Y=input()
    p=len(X)
    q=len(Y)
    Z=[[0 for i in range(q+1)]for j in range(p+1)]
    lcs(X,Y,p,q,Z)

Python: 
def main():
    n = int(input())
    for i in range(n):
        a = input()
        b = input()
        na=len(a)
        nb=len(b)
        array = [[0]*nb]*na
        #array = [[0 for i in range(nb)] for j in range(na)]
        print(array)
        for i in range(na):
            for j in range(nb):
                if i==0:
                    if a[i]==b[j]:
                        array[i][j]=1
                elif j==0:
                    if a[i]==b[j]:
                        array[i][j]=1
                else:
                    c = 0
                    if a[i] == b[j]:
                        c = 1
                    array[i][j] = array[i-1][j-1]+c 
                    max(
                            array[i-1][j],
                            array[i][j-1],
                            array[i-1][j-1]+c)
        print(array[na-1][nb-1])
if __name__ == "__main__":
    main()

Python: import sys, os, math, bisect, itertools, collections, heapq, queue, copy, array

# from scipy.sparse.csgraph import csgraph_from_dense, floyd_warshall
# from decimal import Decimal
# from collections import defaultdict, deque

sys.setrecursionlimit(10000000)

ii = lambda: int(sys.stdin.buffer.readline().rstrip())
il = lambda: list(map(int, sys.stdin.buffer.readline().split()))
fl = lambda: list(map(float, sys.stdin.buffer.readline().split()))
iln = lambda n: [int(sys.stdin.buffer.readline().rstrip()) for _ in range(n)]

iss = lambda: sys.stdin.buffer.readline().decode().rstrip()
sl = lambda: list(map(str, sys.stdin.buffer.readline().decode().split()))
isn = lambda n: [sys.stdin.buffer.readline().decode().rstrip() for _ in range(n)]

lcm = lambda x, y: (x * y) // math.gcd(x, y)

MOD = 10 ** 9 + 7
MAX = float('inf')


def lcs(X, Y):
    dp = []
    for y in Y:
        bgn_idx = 0
        for i, cur_idx in enumerate(dp):
            # 既に探索済みの最長文字列を更新
            chr_idx = X.find(y, bgn_idx) + 1
            if not chr_idx:
                break
            dp[i] = min(chr_idx, cur_idx)
            bgn_idx = cur_idx
        else:
            chr_idx = X.find(y, bgn_idx) + 1
            if chr_idx:
                dp.append(chr_idx)
    return len(dp)


def main():
    if os.getenv("LOCAL"):
        sys.stdin = open("input.txt", "r")

    N = ii()
    for _ in range(N):
        X, Y = iss(), iss()
        print(lcs(X, Y))


if __name__ == '__main__':
    main()