Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	resolve()
}

func resolve() {
	n := scanInt(sc)
	results := []int{}
	for i := 0; i < n; i++ {
		results = append(results, resolveInstance())
	}
	for _, v := range results {
		fmt.Println(v)
	}
	return
}

func resolveInstance() int {
	x, y := scanString(sc), scanString(sc)
	lx, ly := len(x), len(y)
	dp := make([][]int, lx+1)
	dp[0] = make([]int, ly+1)
	for i := 1; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
		dp[i][0] = dp[i-1][0]
		for j := 1; j <= ly; j++ {
			dp[i][j] = dp[i-1][j]
			if dp[i][j] < dp[i][j-1] {
				dp[i][j] = dp[i][j-1]
			}
			if x[i-1] == y[j-1] {
				cL := dp[i-1][j-1] + 1
				if dp[i][j] < cL {
					dp[i][j] = cL
				}
			}
		}
	}
	return dp[lx][ly]
}

const (
	remove = 0 + iota
	match
)

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

Python: def calc_lcs(X, Y):
    max_lcs = 0
    m = len(X)
    n = len(Y)
    X = ' ' + X
    Y = ' ' + Y
    c = [[0]*1001 for i in range(1000+1)]
    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]
            max_lcs = max(max_lcs, c[i][j])
    return max_lcs


if __name__ == '__main__':
    # ??????????????\???
    num = int(input())

    for _ in range(num):
        X = input()
        Y = input()
        # X = 'abcbdab'
        # Y = 'bdcaba'


        # ???????????????
        result = calc_lcs(X, Y)

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

Python: import sys

def lcs(X, Y):
    c = [0 for _ in range(len(Y) + 1)]
    for i in X:
        tmp = c[:]
        for ji, yc in enumerate(Y):
            j = ji + 1
            if i == yc:
                c[j] = tmp[j - 1] + 1
            elif c[j] < c[j - 1]:
                c[j] = c[j - 1]
    return c[-1]

n = int(input())

for i in range(n):
    X = sys.stdin.readline()[:-1]
    Y = sys.stdin.readline()[:-1]
    print(lcs(X, Y))

Python: from collections import defaultdict
q = int(input())
for _ in range(q):
    x = input()
    y = input()
    len_x = len(x)
    len_y = len(y)
    if len_x < len_y:
        len_x, len_y = len_y, len_x
        x, y = y, x
    c = defaultdict(list)
    for i, s in enumerate(x):
        c[s].append(i)
    li = [0] * len_x
    for s in y:
        if s in x:
            for i in c[s][::-1]:
                if i == 0:
                    li[i] = 1
                else:
                    li[i] = max(li[:i]) + 1
    print(max(li))

Python: # coding: utf-8

def array2d(d1, d2, init = None):
    return [[init for _ in range(d2)] for _ in range(d1)]


def solve():
    x = input().strip()
    y = input().strip()

    # dp[i][j]: x[:i], y[:j] ???LCS
    # dp[i][j] = max(dp[i-1][j], dp[i][j-1], dp[i-1][j-1]+1(if x[i]==y[j]))
    dp = array2d(len(x), len(y), 0)
    for i in range(len(x)):
        for j in range(len(y)):
            if i == 0 and j == 0:
                dp[0][0] = int(x[0] == y[0])
                continue
            if i > 0:
                dp[i][j] = max(dp[i][j], dp[i-1][j])
            if j > 0:
                dp[i][j] = max(dp[i][j], dp[i][j-1])
            if i > 0 and j > 0:
                cand = dp[i-1][j-1]
            else:
                cand = 0
            dp[i][j] = max(dp[i][j], cand + (x[i] == y[j]))
    return dp[-1][-1]


def main():
    cases = int(input())
    for i in range(cases):
        print(solve())

main()

Python: import bisect
import collections
import heapq
import itertools
import operator
import sys

dp = [[0] * 1010 for _ in range(1010)]

def lcs(x, y):
    for i, c in enumerate(y):
        if c == x[0]:
            dp[0][i] = 1
    for i, c in enumerate(x):
        if c == y[0]:
            dp[i][0] = 1
    for i in range(len(x)):
        for j in range(len(y)):
            if x[i] == y[j]:
                dp[i][j] = dp[i-1][j-1] + 1
            else:
                dp[i][j] = max(dp[i][j-1], dp[i-1][j])
    return dp[len(x)-1][len(y)-1]

def main():
    n = int(sys.stdin.readline())
    for _ in range(n):
        x = sys.stdin.readline().strip()
        y = sys.stdin.readline().strip()
        print(lcs(x, y))


if __name__ == '__main__':
    main()

Python: def calc_lcs(X, Y):
    from array import array
    m = len(X)
    n = len(Y)
    X = ' ' + X
    Y = ' ' + Y
    c = array('I', [0] * (1001 * 1001))
    for i in range(1, m+1):
        for j in range(1, n+1):
            if X[i] == Y[j]:
                c[i*1001 + j] = c[(i-1)*1001 + j - 1] + 1
            elif c[(i-1)*1001 + j] >= c[i*1001 + j - 1]:
                c[i*1001 + j] = c[(i-1)*1001 + j]
            else:
                c[i*1001 + j] = c[i*1001 + j - 1]
    return 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_lcs(X, Y)

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

Python: def lcs_len(x, y):
    indices = [0]
    for y_i in y:
        t_index = 0
        for i, index in enumerate(indices, 1):
            c_index = x.find(y_i, t_index) + 1
            if c_index:
                if i < len(indices):
                    t_index = indices[i]
                    indices[i] = min(c_index, t_index)
                else:
                    indices.append(c_index)
                    break
    print(len(indices) - 1)


q = int(input())

for i in range(q):
    ax = input()
    ay = input()
    lcs_len(ax, ay)

Python: m = int(input())
for i in range(m):
    str1 = input()
    str2 = input()
    A = [0 for j in range(len(str2)+1)]
    for char1 in str1:
        A_copy = A[:]
        for j,char2 in enumerate(str2):
            if(char1==char2):
                A[j+1] = A_copy[j]+1
            elif(A[j] > A[j+1]):
                A[j+1] = A[j]
    print(A[-1])

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
input:
3
abcbdab
bdcaba
abc
abc
abc
bc

output:
4
3
2

"""
import sys

sys.setrecursionlimit(int(1e5))


def lcs(w1, w2):
    m, n = len(w1), len(w2)
    dp = tuple([0] * (n + 1) for _ in range(m + 1))
    max_l = 0
    for i in range(1, m + 1):
        for j in range(1, n + 1):
            if w1[i - 1] == w2[j - 1]:
                dp[i][j] = dp[i - 1][j - 1] + 1
            else:
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1])
            max_l = max(max_l, dp[i][j])

    return max_l


def lcs_recursive(w1, w2, m, n):
    if m == 0 or n == 0:
        return 0
    elif w1[m - 1] == w2[n - 1]:
        return 1 + lcs_recursive(w1, w2, m - 1, n - 1)
    else:
        return max(lcs_recursive(w1, w2, m, n - 1), lcs_recursive(w1, w2, m - 1, n))


def solve():
    _input = sys.stdin.readlines()
    pair_num = int(_input[0])
    word_list = _input[1:]
    # assert len(word_list) == 2 * pair_num

    for pair in zip(word_list[::2], word_list[1::2]):
        cw1, cw2 = map(lambda x: x.strip(), pair)
        print(lcs(cw1, cw2))
        # l1, l2 = len(cw1), len(cw2)
        # print(lcs_recursive(cw1, cw2, l1, l2))

    return None


if __name__ == '__main__':
    solve()