Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	Q := sc.nextInt()
	for q := 0; q < Q; q++ {
		X, Y := sc.nextStr(), sc.nextStr()
		xLen, yLen := len(X), len(Y)
		dp := make([][]int, xLen+1)
		for i := 0; i <= xLen; i++ {
			dp[i] = make([]int, yLen+1)
		}
		for x := 0; x <= xLen; x++ {
			for y := 0; y <= yLen; y++ {
				if x == 0 || y == 0 {
					dp[x][y] = 0
				} else if X[x-1] == Y[y-1] {
					dp[x][y] = dp[x-1][y-1] + 1
				} else {
					dp[x][y] = max(dp[x-1][y], dp[x][y-1])
				}
			}
		}
		fmt.Fprintln(wtr, dp[xLen][yLen])
	}

	wtr.Flush()
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <cmath>
#include <set>
#include <algorithm>
#include <iomanip>

typedef long long ll;
const ll MOD = 1e9 + 7;
const long long INF = 1LL<<60;
const double PI=3.14159265358979323846;
const int NMAX=100005;
using namespace std;


void solve(string x, string y){
    int lx = x.length();
    int ly = y.length();
    int dp[1001][1001];
    for(int i = 0; i < 1001; i++){
        for(int j = 0; j < 1001; j++){
            dp[i][j] = 0;
        }
    }

    for(int i = 1; i <= lx; i++){
        for(int j = 1; j <= ly; j++){
            if(x[i-1] == y[j-1]){
                dp[i][j] = max(dp[i][j-1],dp[i-1][j-1]+1);
                dp[i][j] = max(dp[i][j],dp[i-1][j]);
            } else {
                dp[i][j] = max(dp[i][j-1],dp[i-1][j-1]);
                dp[i][j] = max(dp[i][j],dp[i-1][j]);
            }
        }
    }

    cout << dp[lx][ly] << endl;
}

int main(){
    int q;
    string x,y;
    cin >> q;
    for(int i = 0; i < q; i++){
        cin >> x >> y;
        solve(x,y);
    }

    return 0;

}

C++: #include<iostream>
#include<string>
using namespace std;

#if 0
所用時間:0.5h

感想:

#endif

int solve(string X, string Y){
  int rows = Y.size();
  int cols = X.size();
  int L[1001][1001] = {}; //L[y][x]の初期化

  //テーブルLの更新
  for(int r = 1; r <= rows; ++r){
    for(int c = 1; c <= cols; ++c){
      if(X[c] == Y[r]) L[r][c] = 1 + L[r-1][c-1];
      else L[r][c] = max(L[r][c-1], L[r-1][c]);
    }
  }

  // //テーブルの表示
  // cout << "Ltable:" << endl;
  // for(int row=0; row <= rows; ++row){
  //   for(int col = 0; col <= cols; ++col){
  //     cout << L[row][col];
  //   }
  //   cout << endl;
  // }

  return L[rows][cols];
}

int main(){
  int q;
  string X, Y;
  cin >> q;

  for(int i = 0; i < q; ++i){
    cin >> X >> Y;

    int ans = solve(X, Y);

    cout << ans << endl;
  }
}

C++: #include <bits/stdc++.h>
using namespace std;

int lcs(string s1, string s2) {
    int n = s1.size(), m = s2.size();

    int c[n + 1][m + 1];
    for (int i = 0; i <= n; i++)
    {
        c[i][0] = 0;
    }
    for (int i = 0; i <= m; i++) {
        c[0][i] = 0;
    }

    // indexを合わせるため、各文字列に空白を挿入
    s1 = ' ' + s1;
    s2 = ' ' + s2;

    int maxl=0;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++) {
            if (s1.at(i) == s2.at(j))
                c[i][j] = 1 + c[i - 1][j - 1];
            else
            {
                c[i][j] = max(c[i - 1][j], c[i][j - 1]);
            }
            maxl = max(maxl, c[i][j]);
        }
    }
    return maxl;
}

int main() {
    int q;
    cin >> q;

    for (int i = 0; i < q; i++)
    {
        string s1, s2;
        cin >> s1 >> s2;
        cout << lcs(s1, s2) << endl;
    }
}

C++: def lcs(str_a,str_b):    
    if len(str_a) == 0 or len(str_b) == 0:
        return 0
    dp = [[0 for kb in range(len(str_b) + 1)] for ka in range(len(str_a) + 1)]
    for i in range(1, len(str_a) + 1):
        for j in range(1, len(str_b) + 1):
            if str_a[i-1] == str_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]])
  #print ("length of LCS is :",dp[len(str_a)][len(str_b)])
    return dp[len(str_a)][len(str_b)]

n=int(input())
for i in range(n):
    s1=input()
    s2=input()
    print(lcs(s1,s2))

C++: #include <bits/stdc++.h>
#define REP0(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define REPB0(i,n) for(int i=n-1;i>=0;i--)
#define REPB1(i,n) for(int i=n;i>0;i--)
#define llong long long
#define INF 2000000000
#define NIL -1
#define N 1000
using namespace std;
int LCS(string X,string Y){
  int C[N+1][N+1];
  int m=X.size();
  int n=Y.size();
  int maxl=0;
  X=' '+X;
  Y=' '+Y;
  C[0][0]=0;
  REP1(i,m) C[i][0]=0;
  REP1(i,n) C[0][i]=0;
  REP1(i,m){
    REP1(j,n){
      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;
}
int main(){
  char a[1000],b[1000];
  string s1,s2;
  int n;
  scanf("%d",&n);
  REP0(i,n){

    scanf("%s %s",a,b);
    s1=a;s2=b;
    printf("%d\n",LCS(s1,s2));
  }
  return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
static const int MAX=1000;

int LCS(string X, string Y) {
    int i, j, maxl=0;
    int C[MAX+1][MAX+1];

    int X_len = X.size();
    int Y_len = Y.size();
    X = ' ' + X;
    Y = ' ' + Y;
    for (i=0; i<=X_len; i++) C[i][0]=0;
    for (j=1; j<=Y_len; j++) C[0][j]=0;

    for (i=1; i<=X_len; i++) {
        for (j=1; j<=Y_len; j++) {
            if (X[i]==Y[j]) {
                C[i][j]=C[i-1][j-1]+1;
                maxl = max(C[i][j], maxl);
            } else C[i][j]=max(C[i-1][j], C[i][j-1]);
        }
    }

    return maxl;
}

int main() {
    int n, i;
    string X, Y;
    
    cin >> n;
    for (i=0; i<n; i++) {
        cin >> X >> Y;
        cout << LCS(X, Y) << endl;
    }

    return 0;
}