Go: package main

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

const max int = 1000 + 1
var A [][]int

func lcs(x, y string) int {
	x = " " + x
	y = " " + y
	for i:=0;i<len(x); i++ {
		for j:=0;j<len(y); j++ {
			A[i][j] = 0
		}
	}
	for i:=1; i<len(x); i++ {
		for j:=1; j<len(y); j++ {
			if x[i] == y[j] {
				A[i][j] = A[i-1][j-1] + 1
			} else if A[i-1][j] > A[i][j-1] {
				A[i][j] = A[i-1][j]
			} else {
				A[i][j] = A[i][j-1]
			}
		}
	}
	return A[len(x)-1][len(y)-1]
}

func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num 
}

func nextStr(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}


func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	A = make([][]int, max)
	for i := range A {
		A[i] = make([]int, max)
	}
	n := nextInt(scanner)
	for i:=0; i<n; i++ {
		x := nextStr(scanner)
		y := nextStr(scanner)
		fmt.Printf("%d\n", lcs(x, y))
	}
}

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]


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].strip(), word_list[k + 1].strip()))

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: def solve(X, Y):
    dp = [[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):
            targetX = X[i-1]
            targetY = Y[j-1]
            if targetX == targetY:
                dp[i][j] = dp[i-1][j-1] + 1
            else:
                dp[i][j] = max(dp[i-1][j], dp[i][j-1])
    return dp[len(X)][len(Y)]

num = int(input())
for i in range(num):
    X = input()
    Y = input()
    print(solve(X,Y))

Python: 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: # 最長共通部分列

def lcs(x, y):
    m = len(x)
    n = len(y)
    c = [0] * (n + 1)
    for i in range(m):
        c2 = c[:]
        for j in range(n):
            if x[i] == y[j]:
                c[j + 1] = c2[j] + 1
            elif c[j + 1] < c[j]:
                c[j + 1] = c[j]
    return c[-1]


n = int(input())
Z = [0] * n
for i in range(n):
    X = input()
    Y = input()
    Z[i] = lcs(X, Y)
for z in Z:
    print(z)

Python: def lcs(x, y):
    ans = [[0]*(len(y)+1) for _ in range(len(x)+1)]
    for i, cx in enumerate(x, 1):
        ao = ans[i-1]
        old = ans[i][0]
        for j, cy in enumerate(y, 1):
            if cx == cy:
                old = ao[j-1] + 1
            else:
                a1, a2 = old, ao[j]
                old = a1 if a1 > a2 else a2
            ans[i][j] = old
    return ans[-1][-1]

def main():
    n = int(input())
    a = []
    for _ in range(n):
        X = input()
        Y = input()
        a.append(lcs(X, Y))
    print('\n'.join(list(map(str, a))))

if __name__ == "__main__":
    main()

Python: from __future__ import print_function
from sys import stdin
def lcs(x, y):
    m = len(x)
    n = len(y)
    c = [[0]*(n + 1) for a in range(m + 2)]
    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 max(max(c))

n = int(raw_input().rstrip())
strs = stdin.readlines()
ret = []
for i in range(n):
    s1 = strs[i*2].rstrip()
    s2 = strs[i*2+1].rstrip()
    ret.append(lcs(s1, s2))
print(*ret, sep="\n")

Python: def edit_distance(s, t):
 s = raw_input()
 t = raw_input()
 dp = {}
 for i in range(len(s) + 1):
  dp[i] = {0: i}
 for j in range(len(t) + 1):
  dp[0][j] = j
 for i in range(1, len(s) + 1):
  for j in range(1, len(t) + 1):
   if (s[i-1] == t[j-1]): 
    d = 0
   else:
    dp[i][j] = min(dp[i-1][j] + 1, dp[i][j-1] + 1, dp[i-1][j-1] + d)
 return dp[len(s)][len(t)]

Python: n = int(input())

cnt=[0 for i in range(n)]

for i in range(n):
	A = []
	A = input()
	B = []
	B = input()

	DP = [[0 for k in range(len(B)+1)] for j in range(len(A)+1)]

	for j in range(len(A)):
		for k in range(len(B)):
			if A[j]==B[k]:
				DP[j+1][k+1]=DP[j][k]+1
			else:
				DP[j+1][k+1]=max(DP[j+1][k], DP[j][k+1])
	cnt[i]=DP[len(A)][len(B)]


for i in range(n):
	print(cnt[i])

Python: 
def main():
    n = int(input())
    for i in range(n):
        a = input()
        b = input()
        na=len(a)
        nb=len(b)
        array = [[1]*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: q = int(input())

l = []
x = ""
y = ""
"""
def lcs(yIndex, xIndex):
    global l, x, y
    if xIndex == 0 and yIndex == 0:
        return 0
    elif xIndex == 0:
        return l[yIndex - 1][0]
    elif yIndex == 0:
        return l[0][xIndex - 1]
    elif x[xIndex] == y[yIndex]:
        return 1 + l[yIndex - 1][xIndex - 1]
    else:
        if l[yIndex][xIndex - 1] > l[yIndex - 1][xIndex]:
            return l[yIndex][xIndex - 1]
        else:
            return l[yIndex - 1][xIndex]
        #return max(l[yIndex][xIndex - 1], l[yIndex - 1][xIndex])
 """
for i in range(q):
    x = input()
    y = input()
 
    yLen = len(y)
    xLen = len(x)
    l = [[-1] * xLen for j in range(yLen)]

    for j in range(yLen):
        for k in range(xLen):
            
            if k == 0 and j == 0:
                l[j][k] = 0
            elif k == 0:
                if x[k] == y[j]:
                    l[j][k] = 1
                else:
                    l[j][k] = max(1, l[j - 1][0])
            elif j == 0:
                if x[k] == y[j]:
                    l[j][k] = 1
                else:
                    l[j][k] = max(1, l[0][k - 1])
            elif x[k] == y[j]:
                l[j][k] =  1 + l[j - 1][k - 1]
            else:
                if l[j][k - 1] > l[j - 1][k]:
                    l[j][k] = l[j][k - 1]
                else:
                    l[j][k] = l[j - 1][k]
            #l[j][k] = lcs(j, k)
 
    print(l[yLen- 1][xLen - 1])