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: import pprint as p
def main():
    n = int(input())
    result = []
    for i in range(n):
        a = input()
        b = input()
        array = [[0 for i in range(len(b))] for j in range(len(a))]
        for i in range(len(a)):
            if a[i]==b[0]:
                array[i][0]=1
        for j in range(len(b)):
            if b[j]==a[0]:
                array[0][j]=1 

        for i in range(1, len(a)):
            for j in range(1, len(b)):
                c = 0
                if a[i] == b[j]:
                    c = 1
                array[i][j] = max(
                                    array[i-1][j],
                                    array[i][j-1],
                                    array[i-1][j-1]+c)
        result.append(array[len(a)-1][len(b)-1])
        #p.pprint(array)
    for i in result:
        print(i)
if __name__ == "__main__":
    main()

Python: import sys

def len_lcs(s1, s2):
    """Find length of the longest common sequence(LCS) of strings s1 and s2.
    The complexity is ~MN.

    >>> len_lcs("abc", "abc")
    3
    >>> len_lcs("abcbdaba", "bdcaba")
    5
    """
    len1 = len(s1)
    len2 = len(s2)
    if len1 == 0 or len2 == 0:
        return 0

    primary = [0] * len1
    secondary = [0] * len1

    for i in range(len2):
        for j in range(len1):
            if s1[j] == s2[i]:
                match = 1
            else:
                match = 0
            if j == 0:
                secondary[j] = max(primary[j], match)
            else:
                secondary[j] = max(secondary[j-1], primary[j],
                                   primary[j-1] + match)

        primary, secondary = secondary, primary

    return primary[len1-1]


def run():
    i = 2 * int(input())
    s = ['', '']
    for line in sys.stdin:
        s[i % 2] = line.strip()
        if i % 2 == 1:
            print(len_lcs(*s))
        i -= 1


if __name__ == '__main__':
    run()

Python: def answer(X, Y):
    m, n = len(X), len(Y)
    C = [[0] * (n + 1) for _ 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][j -1], C[i -1][j])
    return C[m][n]


if __name__ == '__main__':
    q = int(input())
    for _ in range(q):
        X = list(input())
        Y = list(input())
        print(answer(X, Y))

Python: c = [[0 for i in range(1001)] for j in range(1001)]
def lcs(X, Y):
    global c
    m, n = len(X), len(Y)
    for i in range(m+1):
        c[i][0] = 0
    for j in range(n+1):
        c[0][j] = 0
    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]

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

Python: for _ in range(int(input())):
    a = input()
    b = input()
    indices = []
    for cb in b:
        bgn_idx = 0
        for i, cur_idx in enumerate(indices):
            chr_idx = a.find(cb, bgn_idx) + 1
            if not chr_idx:
                break
            if chr_idx < cur_idx:
                indices[i] = chr_idx
            bgn_idx = cur_idx
        else:
            chr_idx = a.find(cb, bgn_idx) + 1
            if chr_idx:
                indices.append(chr_idx)
    print(len(indices))

Python: def lcs(x,y):
    L=[]
    for chk in y:
        bg_i=0
        for i,chr_i in enumerate(L):
            cur_i=x.find(chk,bg_i)+1
            if not cur_i:
                break
            L[i]=min(cur_i,chr_i)
            bg_i=chr_i
        else:
            cur_i=x.find(chk,bg_i)+1
            if cur_i:
                L.append(cur_i)
    return len(L)

n=int(input())
ans=[]
for i in range(n):
    x=input()
    y=input()
    ans.append(lcs(x,y))
for i in ans:
    print(i)

Python: #coding:utf-8
from copy import deepcopy
n = int(input())

def lcs(X,Y):
    m = len(X)
    n = len(Y)
    c = [[False for i in range(n+1)] for j in range(m+1)]
    for i in range(m+1):
        c[i][0] = 0
    for i in range(n+1):
        c[0][i] = 0
    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]
                            
        
for  i in range(n):
    A = input()
    B = input()
    a = lcs(A,B)
    print(a)

Python: q = int(input())
for i in range(q):
    X = input()
    Y = input()
    memo = [[0 for j in range(len(Y)+1)] for i in range(len(X)+1)]
    for i in range(1, len(X)+1):
        for j in range(1, len(Y)+1):
            x = X[:i]
            y = Y[:j]
            if x[-1] == y[-1]:
                memo[i][j] = memo[i-1][j-1] + 1
            else:
                memo[i][j] = max(memo[i-1][j], memo[i][j-1])
    print(memo[len(X)][len(Y)])

Python: def m():
 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:])
if'__main__'==__name__:m()

Python: q = int(input())

for i in range(q):
    X = input()
    Y = input()
    x = len(X)
    y = len(Y)
    X = ' ' + X
    Y = ' ' + Y
    dp = [[0] *(y+1) for i in range(x+1)]
    for j in range(1, x + 1):
        for k in range(1, y + 1):
            if X[j] == Y[k]:
                dp[j][k] = dp[j - 1][k - 1] + 1
            else:
                dp[j][k] = max(dp[j - 1][k],dp[j][k - 1])
    print(dp[x][y])

Python: import sys
sys.setrecursionlimit(10000)

def calc(x,y):
    i = len(x)
    j = len(y)
    if not d[i][j] == None:
        return d[i][j]
    else:
        if x[-1] == y[-1]:
            tmp = calc(x[:-1],y[:-1])+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 = [[0 if i == 0 or j == 0 else None for i in range(len(y)+1)] for j in range(len(x)+1)]
    print(calc(x,y))