Go: package main

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

//Util
func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

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

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

func absInt(a int) int {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func absFloat64(a float64) float64 {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func minFloat64(a, b float64) float64 {
	if a > b {
		return b
	} else {
		return a
	}
}

func str2Int(s string) int {
	n, _ := strconv.Atoi(s)
	return n
}

//Main
var sc = bufio.NewScanner(os.Stdin)
var q int
var X, Y string

func lcs(X, Y string) int {
	lenX := len(X)
	lenY := len(Y)
	dp := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		dp[i] = make([]int, lenY+1)
	}

	res := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if X[i-1] == Y[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
			//fmt.Println(dp)
			res = maxInt(res, dp[i][j])
		}

	}
	return res
}

func main() {
	sc.Split(bufio.ScanWords)
	q = nextInt()

	for i := 0; i < q; i++ {
		X = nextStr()
		Y = nextStr()

		fmt.Println(lcs(X, Y))
	}
}

Python: # http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_C&lang=ja
# 最長共通部分文字列
import sys
read = sys.stdin.read
readline = sys.stdin.readline
readlines = sys.stdin.readlines

# dp[i][j] := Sのi番目までとTのj番目までのLCS
# アルゴリズム的には正しいがTLE
def LCS(S, T):
    n = len(S)
    m = len(T)

    dp = [[0] * (m+1) for _ in range(n+1)]

    for i in range(n):
        S_i = S[i]
        for j in range(m):
            if S_i == T[j]:
                dp[i+1][j+1] = dp[i][j] + 1
            else:
                dp[i+1][j+1] = max(dp[i+1][j], dp[i][j+1])
    
    return dp[n][m]


def LCS2(S, T):
    L = []
    for t in T:
        t_idx = 0  # 検索開始位置
        for i, cur_idx in enumerate(L):
            chr_idx = S.find(t, t_idx) + 1
            if not chr_idx:
                break
            L[i] = min(cur_idx, chr_idx)
            t_idx = cur_idx
        else:
            chr_idx = S.find(t, t_idx) + 1
            if chr_idx:
                L.append(chr_idx)
    
    return len(L)


def main():
    q = int(readline())
    xy = read().split()

    ans = []
    for X, Y in zip(*[iter(xy)]*2):
        ans.append(LCS2(X, Y))

    print("\n".join(map(str, ans)))


if __name__ == "__main__":
    main()

Python: q = int(input())

def lcs(X, Y):
    dp = [0]*(len(Y)+1)
    
    for x in X:
        tmp = dp[:]
        for j, y in enumerate(Y):
            if x == y:
                dp[j+1] = tmp[j] + 1
            elif dp[j+1] < dp[j]:
                dp[j+1] = dp[j]
                               
    return dp[-1]
    
for _ in range(q):
    X = input()
    Y = input()
    print(lcs(X, Y))

Python: import sys

sys.setrecursionlimit(1000000)


def lcd(x0, y0):
    lx, ly = len(x0), len(y0)
    memo = [[None] * ly for _ in range(lx)]

    def memoize(x, y):
        if x < 0 or y < 0:
            return 0
        if memo[x][y] is not None:
            return memo[x][y]
        result = memo[x][y] = main(x, y)
        return result

    def main(x, y):
        if x0[x] == y0[y]:
            return memoize(x - 1, y - 1) + 1
        return max(memoize(x - 1, y), memoize(x, y - 1))

    return main(lx - 1, ly - 1)


n = int(input())
while n:
    print(lcd(input(), input()))
    n -= 1

Python: from collections import defaultdict
from bisect import bisect_left, bisect, insort_left, insort
INF = 10000
def lcs(s1, s2):
    c = defaultdict(list)
    for i, s in enumerate(s1):
        c[s].append(i)
    for s in set(s2):
        c[s].append(INF)
    def g(li, a):
        for i in li:
            if i >= a:
                return i
        return -1
    dp = []
    for s2_k in s2:
        bgn_idx = 0
        for i, cur_idx in enumerate(dp):
            chr_idx = c[s2_k][bisect_left(c[s2_k], bgn_idx)]
            if chr_idx == INF:
                break
            dp[i] = min(cur_idx, chr_idx + 1)
            bgn_idx = cur_idx
        else:
            chr_idx = c[s2_k][bisect_left(c[s2_k], bgn_idx)]
            if chr_idx != INF:
                dp.append(chr_idx + 1)
    return len(dp)
def solve():
    N = int(input())
    for _ in range(N):
        x = input()
        y = input()
        print(lcs(x, y) if len(x) > len(y) else lcs(y, x))
solve()

Python: 
def LCS(x, y):
    len_x = len(x)
    len_y = len(y)
    
    dp = {}
    for i in range(len_x + 1):
        dp[i] = {0: 0}
    for j in range(len_y + 1):
        dp[0][j] = 0
    
    for i in range(1, len_x + 1):
        for j in range(1, len_y + 1):
            if x[i-1] == y[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[len_x][len_y]

q = int(raw_input())
for i in range(q):
    X = raw_input()
    Y = raw_input()
    print(LCS(X, Y))

Python: from itertools import product

q = int(input().rstrip())
data_set = [[[i for i in input().rstrip()],
             [i for i in input().rstrip()]] for i in range(q)]
common_list = [[0] * 2000 for i in range(2000)]


def lcs(X: list, Y: list):
    global common_list
    m, n = len(X), len(Y)
    for i, k in product(range(1, m + 1), range(1, n + 1)):
            common_list[i][k] = common_list[i - 1][k - 1] + 1 if X[i - 1] == Y[k - 1] else max(common_list[i - 1][k], common_list[i][k - 1])
    return common_list[m][n]

[print(lcs(l, r)) for l, r in data_set]

Python: import sys
readline = sys.stdin.readline
from collections import defaultdict
from bisect import bisect_left, bisect, insort_left, insort
INF = 10000
def lcs(s1, s2):
    c = defaultdict(list)
    for i, s in enumerate(s1):
        c[s].append(i)
    for s in set(s2):
        c[s].append(INF)
    dp = []
    for s2_k in s2:
        bgn_idx = 0
        for i, cur_idx in enumerate(dp):
            chr_idx = c[s2_k][bisect_left(c[s2_k], bgn_idx)]
            if chr_idx == INF:
                break
            dp[i] = min(cur_idx, chr_idx + 1)
            bgn_idx = cur_idx
        else:
            chr_idx = c[s2_k][bisect_left(c[s2_k], bgn_idx)]
            if chr_idx != INF:
                dp.append(chr_idx + 1)
    return len(dp)
def solve():
    N = int(input())
    for _ in range(N):
        x = readline().strip()
        y = readline().strip()
        print(lcs(x, y) if len(x) > len(y) else lcs(y, x))
solve()

Python: q = int(input().rstrip())
for i in range(q):
    x = input().rstrip()
    y = input().rstrip()
    n = len(x)
    m = len(y)
    dp1 = [0]*(m+1)
    for i in range(n):
        s = x[i]
        dp2 = dp1[:]
        for j in range(m):
            if s == y[j]:
                dp1[j+1] = dp2[j]+1
            elif dp1[j+1] < dp1[j]:
                dp1[j+1] = dp1[j]
    print(dp1[-1])

Python: q = int(input())


for __ in range (q):

    S1 = input()
    S2 = input()
    dp = [[0 for i in range(len(S2)+1)] for j in range(len(S1)+1)]


    for i in range (len(S1)):
        for j in range (len(S2)):
            if S1[i] != S2[j]:
                dp[i+1][j+1] = max(dp[i+1][j],dp[i][j+1])
            else:
                dp[i+1][j+1] = (dp[i][j]+1)

    print(dp[len(S1)][len(S2)])

Python: n = int(input())

for i in range(n):
    s = list(input())
    t = list(input())
    dp = [[0 for j in range(len(s)+1)] for k in range(len(t)+1)]

    for j in range(len(s)):
        for k in range(len(t)):
            if s[j]==t[k]:
                dp[k+1][j+1] = max(dp[k][j]+1,dp[k+1][j+1])
            else:
                dp[k+1][j+1] = max(dp[k+1][j+1],dp[k+1][j])
                dp[k+1][j+1] = max(dp[k+1][j+1],dp[k][j+1])
    print(dp[len(t)][len(s)])