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] = dp[i-1][j-1]+1
				} else if S[i-1] != T[j-1] && dp[i-1][j] > dp[i][j-1] {
					dp[i][j] = dp[i-1][j]
				} else {
					dp[i][j] = dp[i][j-1]
				}
				// 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: import sys

c = [[0 for _ in range(1001)] for _ in range(1001)]
for _ in range(int(sys.stdin.readline())):
    x = sys.stdin.readline().rstrip()
    y = sys.stdin.readline().rstrip()
    c[0][0]=0
    for i,xi in enumerate(x):
        for j,yj in enumerate(y):
            if xi==yj:
                c[i+1][j+1] = c[i][j]+1
            elif c[i][j+1] > c[i+1][j]:
                c[i+1][j+1] = c[i][j+1]
            else:
                c[i+1][j+1] = c[i+1][j]
            
    print(c[len(x)][len(y)])

Python: # ライブラリのインポート
#import re #正規表現
import sys
#import heapq
#import collections
#import math

def main():
    q = int(input())
    STR = [str.strip("\n") for str in sys.stdin]
    for i in range(q):
        x = STR[2*i]
        y = STR[2*i+1]
        print(lcs(x,y))


def lcs(x, y):
    dp = []
    for y_k in y:
        ps = 0
        for i, pdp in enumerate(dp):
            p = x.find(y_k, ps) + 1 #.find method returns -1 if there is no element
            if not p: break
            dp[i] = min(p,pdp)
            ps = pdp
        else: #else block is executed when for block has done completedly
            p = x.find(y_k, ps) + 1
            if p: dp.append(p)
    return len(dp)


if __name__ == '__main__':
    main()

Python: n = int(input())
for i in range(n):
    a = input()
    b = input()
    L = [[0 for j  in range(len(a) + 1)] for k in range(len(b) + 1)]
    for  m in range(1, len(a) + 1):
        for n in range(1, len(b) + 1):
            if a[m-1] == b[n-1]:
                L[n][m] = L[n-1][m-1] + 1
            else:
                L[n][m] = max(L[n-1][m], L[n][m-1])
    print(L[-1][-1])

Python: from typing import List


def compute_lcs(x_str: str, y_str: str) -> int:
    if len(x_str) <= len(y_str):
        shorter_str, longer_str = x_str, y_str
    else:
        shorter_str, longer_str = y_str, x_str

    lcs_idx: List[int] = []
    for s_ch in shorter_str:
        l_bgn_idx = 0
        for i, l_cur_idx in enumerate(lcs_idx):
            l_idx = longer_str.find(s_ch, l_bgn_idx)
            if -1 == l_idx:
                break
            lcs_idx[i] = min(l_cur_idx, l_idx)
            l_bgn_idx = l_cur_idx + 1  # Move to the next ch.
        l_idx = longer_str.find(s_ch, l_bgn_idx)
        if -1 != l_idx:
            lcs_idx.append(l_idx)
    return len(lcs_idx)


if __name__ == "__main__":
    num_pairs = int(input())

    for _ in range(num_pairs):
        x_str = input()
        y_str = input()
        lcs = compute_lcs(x_str, y_str)
        print(f"{lcs}")

Python: 
n=int(input())
cnt=[]
for k in range(n):
    a=input()
    b=input()
    lc=[[0 for j in range(len(b)+1)]for i in range(len(a)+1)]
    for i in range(len(a)):
        for j in range(len(b)):
            if a[i]==b[j]:
                lc[i+1][j+1]=lc[i][j]+1
            else:
                if lc[i][j+1]>lc[i+1][j]:
                    lc[i+1][j+1]=lc[i][j+1]
                else:
                    lc[i+1][j+1]=lc[i+1][j]
    cnt.append(lc[-1][-1])
for i in range(len(cnt)):
    print(cnt[i])