Go: package main

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

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func bordersInt(in_map [][]int, invalid int) [][]int{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]int, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]int, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func bordersString(in_map [][]string, invalid string) [][]string{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]string, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]string, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func maxInt(args... int) int{
	sort.Ints(args)
	return args[len(args)-1]
}

func main(){
	buf := make([]byte, 0)
    sc.Buffer(buf, 1000000009)
	var n int 
	fmt.Scan(&n)
	dp := make([][]int, 1003)
	for i:=0; i<1003; i++ {
		dp[i] = make([]int, 1003)
	}
	input_lines := scanStringLine(2*n)
	for i:=0; i<n; i++ {
		S, T := input_lines[2*i], input_lines[2*i+1]
		lenS, lenT := len(S), len(T)
		for i:=1; i<lenS+1; i++ {
			for j:=1; j<lenT+1; j++ {
				if S[i-1] == T[j-1] {
					dp[i][j] = maxInt(dp[i-1][j-1]+1, dp[i-1][j], dp[i][j-1])
				} else {
					dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
				}
			}
		}
		fmt.Println(dp[lenS][lenT])
	}
}

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 for i in range(n+1)] for i in range(m+1)]
    c = [None]*(m+1)
    for i in range(m+1):
        c[i] = [0]*(n+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 str(c[m][n])

q = int(input())
for i in range(q):
    X = input()
    Y = input()
    print(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
            else:
                count_list[i][j] = max(count_list[i - 1][j], count_list[i][j - 1])

    return count_list[m][n]


# def lcs_better(A, B):
#     cost_history = [None]
#     for ele in B:
#         for index in range(len(cost_history) - 1, -1, -1):
#             # ???????¬??????°????????????????§???¨A??\?????°??????(ele), ????????°?????????
#             found = A.find(ele, cost_history[index])
#             if found != -1:
#                 if index + 1 < len(cost_history):
#                     cost_history[index + 1] = min(cost_history[index + 1], found + 1)
#                 # ??¨???????????°?????¢?????°?????¶?????°????????´???
#                 else:
#                     assert index + 1 == len(cost_history)
#                     cost_history.append(found + 1)
# 
#     return len(cost_history) - 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].strip(), word_list[k + 1].strip()))

Python: q = int(input())

l = []
x = ""
y = ""

for i in range(q):
    x = input()
    y = input()
 
    yLen = len(y)
    xLen = len(x)
    l = [[0] * xLen for j in range(yLen)]

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

Python: n=int(input())
ans=[]
for k in range(n):
    s1=input()
    s2=input()
    dp=[[0 for i in range(len(s2)+1)] for j in range(len(s1)+1)]
    for i in range(1,len(s1)+1):
        for j in range(1,len(s2)+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])


    ans.append(dp[len(s1+1)][len(s2+1)])
for a in ans:
    print(a)

Python: q = int(input())

def lcs(X, Y):
    x_len = len(X)
    y_len = len(Y)
    dp = [[0 for _ in range(y_len+1)] for _ in range(x_len+1)]
    
    for i, x in enumerate(X):
        for j, y in enumerate(Y):
            if x == y:
                dp[i][j] = dp[i-1][j-1] + 1
            else:
                dp[i][j] = max(dp[i-1][j], dp[i][j-1])
                               
    return max(max(dp))
    
for _ in range(q):
    X = input()
    Y = input()
    print(lcs(X, Y))

Python: for _ in[0]*int(input()):
 X,Y=' '+input(),' '+input();m,n=len(X),len(Y);c=[[0]*n for _ in[0]*m]
 for i in range(1,m):
  for j in range(1,n):c[i][j]=(max(c[i-1][j],c[i][j-1]),1+c[i-1][j-1])[X[i]==Y[j]]
 print(c[m-1][n-1])

Python: import bisect

INF = float('inf')
q = int(input())
for i in range(q):
    x = input()
    y = input()
    dic = {}
    for i,xx in enumerate(x):
        if xx in dic : dic[xx].append(i)
        else : dic[xx] = [i]
    inc = []
    size = -1
    for j,yy in enumerate(y):
        if not (yy in dic):continue
        inc.append([])
        size += 1
        for k in dic[yy]:
            inc[size].append(k)
    #incのLISを求めればよい
    n = len(inc)
    dp =  [INF for i in range(n)]
    temp = [INF for i in range(n)]

    for ii in inc:
        for i in ii:
            p = bisect.bisect_left(dp, i)
            temp[p] = min(i,temp[p])
        dp = temp[:]


    print(bisect.bisect_left(dp, INF))

Python: ans=[]
n=int(input())
for i in range(n):
    X=input()
    Y=input()
    com=[0]
    for i in Y:
        for j in range(len(com)-1,-1,-1):
            tmp=X.find(i,com[j])
            if tmp+1:
                if j+1<len(com):
                    com[j+1]=min(com[j+1],tmp+1)
                else:
                    com.append(tmp+1) 
    ans.append(len(com)-1)
for i in range(n):
    print(ans[i])