Go: package main

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

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func lcs(a, b string) int {
	lenA := len(a)
	lenB := len(b)
	dp := make([][]int, lenA+1)
	for i := range dp {
		dp[i] = make([]int, lenB+1)
	}

	for i := 1; i <= lenA; i++ {
		for j := 1; j <= lenB; j++ {
			if a[i-1] == b[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = max(dp[i][j-1], dp[i-1][j])
			}
		}
	}
	return dp[lenA][lenB]
}

func main() {
	n := scanInt()
	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		a := scanString()
		b := scanString()
		fmt.Fprintln(w, lcs(a, b))
	}
	w.Flush()
}

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])

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

????????±?????¨??????
"""
# 4/5??§Time Limit Exceeded 5.94s ????????????5s??\???????????????????????????



def prep_array(X, Y):
    """ ??????0???2?¬???????????????¨??????????????????????????\????????????????????§??????????????????????¨?(1000+1) """
    c = [[0]*1001 for _ in range(1000+1)]
    return c


def check_max(array):
    """ 2?¬????????????????????????§??????????????? """
    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):
    """
    X[i]???for j?????????????????????????????°????????????????????§???
    4/5 ?????????????????????????????¨????????????????????????????????°??§6.5?§?
    """
    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:
                row[j] = pre_row[j - 1] + 1
                if row[j] > max_lcs:
                    max_lcs = row[j]
            elif pre_row[j] >= row[j - 1]:
                row[j]= pre_row[j]
            else:
                row[j] = row[j - 1]
        pre_row = row
    return max_lcs



def calc_lcs3(X, Y, c):
    """
    X[i]???for j?????????????????????????????°????????????????????§???
    4/5 ?????????????????????????????¨????????????????????????????????°??§7.1?§?
    """
    m = len(X)
    n = len(Y)
    X = ' ' + X
    Y = ' ' + Y

    pre_row = c[0]
    for i in range(1, m+1):
        row = c[i]
        XX = X[i]
        for j in range(1, n+1):
            if XX == Y[j]:
                row[j] = pre_row[j - 1] + 1
            elif pre_row[j] >= row[j - 1]:
                row[j] = pre_row[j]
            else:
                row[j] = row[j - 1]
        pre_row = row
    return check_max(c)



def calc_lcs2(X, Y, c):
    """
    c[i][j]????????¢????????????????????????????????§?????????????????¨?????????????????°??????????????????????????£??????????????§???
    4/5 ?????????????????????????????¨????????????????????????????????°??§8.2?§?
    """
    m = len(X)
    n = len(Y)
    X = ' ' + X
    Y = ' ' + Y

    pre_row = c[0]
    for i in range(1, m+1):
        row = c[i]
        for j in range(1, n+1):
            if X[i] == Y[j]:
                row[j] = pre_row[j - 1] + 1
            elif pre_row[j] >= row[j - 1]:
                row[j] = pre_row[j]
            else:
                row[j] = row[j - 1]
        pre_row = row
    return check_max(c)



def calc_lcs(X, Y, c):
    """
    ??????????????¢?????´????????????????????????????£?????????????
    4/5 ?????????????????????????????¨????????????????????????????????°??§12.5?§?
    """
    m = len(X)
    n = len(Y)
    X = ' ' + X
    Y = ' ' + Y

    for i in range(1, m+1):
        for j in range(1, n+1):
            if X[i] == Y[j]:
                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 check_max(c)


if __name__ == '__main__':
    # ??????????????\???
    num = int(input())
    # f = open('input.txt')
    # num = int(f.readline())

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

        # ???????????????
        result = calc_lcs4(X, Y, prep_array(X, Y))

        # ???????????¨???
        print(result)

Python: n=int(input())

for i in range(n):
    a=list(input())
    b=list(input())

    r=[[0 for j in range(len(b)+1)]for i in range(len(a)+1)]

    for j in range(1,len(a)+1):
        for k in range(1,len(b)+1):
            c=max(r[j-1][k-1],r[j-1][k],r[j][k-1])
            if a[j-1]==b[k-1]:
                c=max(r[j-1][k-1]+1,r[j-1][k],r[j][k-1])
            
            r[j][k]=c
            print(r[j][k],end="")
        print(" ",end="\n")
    
    print(r[len(a)][len(b)])