Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)
	for i := 0; i < n; i++ {
		x := getNextString(scanner)
		y := getNextString(scanner)

		fmt.Fprintln(writer, lcs(x, y))
	}

	writer.Flush()
}

func lcs(x, y string) int {
	lx := len(x)
	ly := len(y)
	dp := make([][]int, lx+1)
	for i := 0; i <= lx; i++ {
		dp[i] = make([]int, ly+1)
	}
	for i := 0; i < lx; i++ {
		for ii := 0; ii < ly; ii++ {
			if x[i] == y[ii] {
				dp[i+1][ii+1] = dp[i][ii] + 1
				continue
			}
			dp[i+1][ii+1] = dp[i][ii+1]
			if dp[i+1][ii] > dp[i+1][ii+1] {
				dp[i+1][ii+1] = dp[i+1][ii]
			}
		}
	}
	return dp[lx][ly]
}

Python: def lcs(x, y):
    m, n = len(x), len(y)
    dp = [[0 for j in range(n+1)] for i in range(m+1)]

    for i in range(1, m+1):
        for j in range(1, n+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[m][n]


def main():
    q = int(input())

    for i in range(q):
        x, y = input(), input()
        print(lcs(x, y))


if __name__ == '__main__':
    main()

Python: 
def lcs():
    A = input()
    B = input()

    m = len(A)
    n = len(B)

    dp = [[0 for i in range(n + 1)] for j in range(m + 1)]

    maxl = 0

    for i in range(1, m + 1):
        for j in range(1, n + 1):
            if A[i - 1] == B[j - 1]:
                dp[i][j] = dp[i - 1][j - 1] + 1
            else:
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1])

            maxl = max(maxl, dp[i][j])

    return maxl

n = input()
for _ in range(n):
    print(lcs())

Python: def len_LCS(X,Y):
    D = {}
    def main(X,Y):
        if len(X) == 0: return 0
        if (X,Y) in D: return D[(X,Y)]
        if len(X) == 1:
            D[(X,Y)] = 1 if X[0] in Y else 0
        elif X[0] in Y:
            if Y.index(X[0]) == len(Y)-1:
                D[(X,Y)] = max(1,main(X[1:],Y[:])) 
            else: 
                D[(X,Y)]=  max(main(X[1:],Y[Y.index(X[0])+1:]) + 1,\
                               main(X[1:],Y[:]))
        else:
             D[(X,Y)] = main(X[1:],Y[:]) 
        return D[(X,Y)]
    return main(X,Y)
        
if __name__=='__main__':
    n = int(input())
    for _ in range(n):
        X = input()
        Y = input()
        print(len_LCS(X,Y))

Python: def main():
    num = int(input())
    for i in range(num):
        X = " " + input()
        Y = " " + input()
        lx = len(X)
        ly = len(Y)
        max = 0
        XY = [[0] * ly for i in range(lx)]
        for j in range(1,lx):
            for k in range(1,ly):
                if X[j] == Y[k]:
                    XY[j][k] = XY[j-1][k-1] + 1
                elif XY[j-1][k] > XY[j][k-1]:
                    XY[j][k] = XY[j-1][k]
                else:
                    XY[j][k] = XY[j][k-1]
                if max < XY[j][k]:
                    max = XY[j][k]
        print(max)

if __name__ == '__main__':
    main()

Python: for _ in range(int(input())):
    X, Y = input(), input()
    X_len = len(X)
    Y_len = len(Y)
    dp = [[0] * (Y_len+1) for x in range(X_len+1)]
    for x in range(1, X_len + 1):
        pre = dp[x-1]
        tmp = dp[x]
        for y in range(1, Y_len + 1):
            if X[x-1] == Y[y-1]:
                tmp[y] = pre[y-1] + 1
            else:
                tmp[y] = max(tmp[y-1], pre[y])
    print(dp[-1][-1])

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[len(a)][len(b)])

Python: # -*- coding: utf-8 -*-
import numpy as np

def lcs_sol(x, y):
    n = len(x)
    m = len(y)
    dp = np.zeros((n + 1) * (m + 1)).reshape(n + 1, m + 1)

    for i in range(1, n + 1):
        for j in range(1, m + 1):
            if x[i - 1] == y[j - 1]:
                dp[i][j] = dp[i - 1][j - 1] + 1
            else:
                dp[i][j] = max(dp[i - 1][j], dp[i][j - 1])

    return dp[n][m]


if __name__ == '__main__':
    import sys
    q = int(sys.stdin.readline().strip())
    for i in range(q):
        x = sys.stdin.readline().strip()
        y = sys.stdin.readline().strip()
        print(lcs_sol(x, y))

Python: def lcs_better(X, Y):
    costs = [0]
    for c in Y:
        for i in range(len(costs) - 1, -1, -1):
            tmp = X.find(c, costs[i])
            if tmp + 1:
                if i + 1 < len(costs):
                    costs[i + 1] = min(costs[i + 1], tmp + 1)
                else:
                    costs.append(tmp + 1)
    return len(costs) - 1


def answer(X, Y):
    m, n = len(X), len(Y)
    C = [[0] * (n + 1) for _ in range(m + 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
            else:
                C[i][j] = max(C[i][j -1], C[i -1][j])
    return C[m][n]


if __name__ == '__main__':
    q = int(input())
    for _ in range(q):
        X = list(input())
        Y = list(input())
        print(lcs_better(X, Y))

Python: def lcs_len(x, y):
    indices = [0]
    for y_i in y:
        t_index = c_index = 0
        for i in range(1, len(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)
n = int(input())
for i in range(n):
    lcs_len(input(), input())

Python: def main():
    N = int(input())

    string_data = [input() for _ in range(N * 2)]

    for _ in range(N):
        s = string_data.pop(0)
        t = string_data.pop(0)

        dp = [0] * (len(t) + 1)

        for i, sc in enumerate(s):
            tmp = dp[:]
            for j, tc in enumerate(t):
                if sc == tc:
                    dp[j + 1] = tmp[j] + 1
                elif dp[j + 1] < dp[j]:
                    dp[j + 1] = dp[j]

        print(dp[-1])


if __name__ == '__main__':
    main()

Python: def lcs(x, y):
    lx = len(x)
    ly = len(y)
    pcsl = [[0 for i in range(ly + 1)] for j in range(lx + 1)]
    for i in range(lx):
        for j in range(ly):
            if x[i] == y[j]:
                pcsl[i][j] = pcsl[i - 1][j - 1] + 1
            else:
                pcsl[i][j] = max(pcsl[i - 1][j], pcsl[i][j - 1])
    print(pcsl[i][j])


q = int(input())

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

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=c+1
            
            r[j][k]=c
    print(r[len(a)][len(b)])

Python: for _ in[0]*int(input()):
 X,z=input(),[]
 for y in input():
  s=i=0
  for k in z:
   t=X.find(y,s)+1
   if not t:break
   if t<k:z[i]=t
   s=k;i+=1
  else:
   t=X.find(y,s)+1
   if t:z+=[t]
 print(len(z))