Go: package main

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

const N = 1001

func max(x, y int) int {
	if x > y {
		return x
	}
	return y
}

func lcs(x, y string) int {
	var c [N][N]int
	m := len(x)
	n := len(y)
	var maxl int

	x = " " + x
	y = " " + y

	for i := 1; i <= m; i++ {
		for j := 1; j <= n; j++ {
			if x[i] == y[j] {
				c[i][j] = c[i-1][j-1] + 1
			} else {
				c[i][j] = max(c[i-1][j], c[i][j-1])
			}
			maxl = max(maxl, c[i][j])
		}
	}
	return maxl
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	q, _ := strconv.Atoi(sc.Text())

	var out bytes.Buffer
	for i := 0; i < q; i++ {
		sc.Scan()
		s1 := sc.Text()
		sc.Scan()
		s2 := sc.Text()
		out.WriteString(fmt.Sprintf("%d\n", lcs(s1, s2)))
	}
	return strings.TrimRight(out.String(), "\n")
}

func main() {
	fmt.Println(answer(os.Stdin))
}

Python: #!/usr/bin/env python3
import sys
sys.setrecursionlimit(15000)
n = int(sys.stdin.readline())

def lcs(X,Y):
  n_y = len(Y)
  n_x = len(X)
  #dp = [[0]*(n_x+1) for _ in range(n_y+1)]
  dp = [0]*(n_x+1)
  for i_y in range(n_y):
    ndp = dp.copy()
    for i_x in range(n_x):
      if X[i_x] == Y[i_y]:
        #dp[i_y+1][i_x+1] = dp[i_y][i_x] + 1
        ndp[i_x+1] = dp[i_x] + 1
      elif dp[i_x+1] < ndp[i_x]:
        #dp[i_y+1][i_x+1] = max(dp[i_y+1][i_x],dp[i_y][i_x+1])
        ndp[i_x+1] = ndp[i_x]
    dp = ndp
    #print(dp)
    #return(dp[-1][-1])
  return(dp[-1])

ret = []
inp = sys.stdin.readlines()
for i in range(n):
  X = inp[2*i].rstrip()#[:-1]#input()
  Y = inp[2*i+1].rstrip()#[:-1]#input()
  ret.append(lcs(X,Y))
  #print

print(*ret,sep="\n")

Python: n = int(input())

def lcs(x, y):
    xlen = len(x)
    ylen = len(y)
    if xlen == 0 or ylen == 0:
        return 0
    elif x[xlen-1] == y[ylen-1]:
        return lcs(x[:-1], y[:-1]) + 1
    else:
        return max(lcs(x, y[:-1]), lcs(x[:-1], y))

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

Python: def lcs(X,Y):
    f=[[0 for i in range(len(Y))]for j in range(len(X))]
    for i in range(1,len(X)):
        for j in range(1,len(Y)):
            if X[i]==Y[j]:
                f[i][j]=f[i-1][j-1]+1
            else:
                f[i][j]=max(f[i-1][j],f[i][j-1])
    return f[len(X)-1][len(Y)-1]

q=int(input())
A=[0 for i in range(q)]
for i in range(q):
    X=input()
    Y=input()
    A[i]=lcs(X,Y)

for i in range(q):
    print(A[i])

Python: """
problem statment url: http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_C
"""

from __future__ import division
from sys import stdin, maxint

def lcs(s1, s2):
	dp = [[0 for _ in xrange(len(s2) + 1)] for _ in xrange(2)]

	for i in xrange(1, len(s1) + 1):
		for j in xrange(1, len(s2) + 1):
			if s1[i - 1] == s2[j - 1]:
				dp[i & 1][j] = dp[1 - i & 1][j - 1] + 1
			else:
				dp[i & 1][j] = max(dp[1 - i & 1][j], dp[i & 1][j - 1])

	return dp[len(s1) & 1][len(s2)]

if __name__ == '__main__':
	tc = int(stdin.readline())
	for _ in range(tc):
		sa = stdin.readline().strip()
		sb = stdin.readline().strip()
		print(lcs(sa, sb))

Python: #JOI
def main():
    X=input()
    Y=input()
    dp=[[0 for y in range(1+len(Y))] for x in range(1+len(X))]
    for x in range(len(X)):
        for y in range(len(Y)):
            now=0
            dp[x][y]=max(dp[x-1][y],dp[x][y-1])
            for x1 in range(Y[:y+1].count(X[x])):
                idx=now+Y[now:y+1].index(X[x])
                now=idx+1
                dp[x][y]=max(dp[x-1][idx-1]+1,dp[x][y])
            now=0
            for y1 in range(X[:x+1].count(Y[y])):
                idx=now+X[now:x+1].index(Y[y])
                now=idx+1
                dp[x][y]=max(dp[idx-1][y-1]+1,dp[x][y])
    print(dp[len(X)-1][len(Y)-1])
for i in range(int(input())):
    main()