Go: package main

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

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func bordersInt(in_map [][]int, invalid int) [][]int{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]int, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]int, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func bordersString(in_map [][]string, invalid string) [][]string{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]string, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]string, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func maxInt(args... int) int{
	sort.Ints(args)
	return args[len(args)-1]
}

func main(){
	buf := make([]byte, 0)
    sc.Buffer(buf, 1000000009)
	var n int 
	fmt.Scan(&n)
	dp := make([][]int, 1003)
	for i:=0; i<1003; i++ {
		dp[i] = make([]int, 1003)
	}
	input_lines := scanStringLine(2*n)
	for i:=0; i<n; i++ {
		S, T := input_lines[2*i], input_lines[2*i+1]
		lenS, lenT := len(S), len(T)
		for i:=1; i<lenS+1; i++ {
			for j:=1; j<lenT+1; j++ {
				if S[i-1] == T[j-1] {
					dp[i][j] = dp[i-1][j-1]+1
				} else if S[i-1] != T[j-1] && dp[i-1][j] > dp[i][j-1] {
					dp[i][j] = dp[i-1][j]
				} else {
					dp[i][j] = dp[i][j-1]
				}
				// if S[i-1] == T[j-1] {
				// 	dp[i][j] = maxInt(dp[i-1][j-1]+1, dp[i-1][j], dp[i][j-1])
				// } else {
				// 	dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
				// }
			}
		}
		fmt.Println(dp[lenS][lenT])
	}
}

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

int lcs(string X, string Y) {
  int dp[1000 + 1][1000 + 1];
  int max = 0;
  int m = X.size();
  int n = Y.size();
  X = ' ' + X;
  Y = ' ' + Y;

  for (int i = 1; i <= m; i++)
    dp[i][0] = 0;

  for (int i = 1; i <= n; i++)
    dp[0][i] = 0;

  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (X[i] == Y[j])
	dp[i][j] = dp[i-1][j - 1] + 1;
      else if (dp[i - 1][j] >= dp[i][j - 1])
	dp[i][j] = dp[i - 1][j];
      else
	dp[i][j] = dp[i][j - 1];

      max = (max < dp[i][j]) ? dp[i][j] : max;
    }
  }

  return max;
}

int main(int argc, char const *argv[]) {
  int N;
  cin >> N;

  for (int i = 0; i < N; i++) {
    string X, Y;
    cin >> X >> Y;

    cout << lcs(X, Y) << endl;
  }

  return 0;
}

C++: #include <iostream>
#define MAX 1010

int C[MAX][MAX];

int main() {
  int n;
  std::cin >> n;
  int answers[160];

  for(int m=0; m<n; ++m) {
    std::string X;
    std::string Y;
    std::cin >> X;
    std::cin >> Y;

    // initialize
    for(int k=0; k<MAX; ++k) {
      for(int p=0; p<MAX; ++p) C[k][p] = 0;
    }

    // lcs
    int xlen = X.size();
    int ylen = Y.size();

    X = ' ' + X;
    Y = ' ' + Y;

    for(int i=1; i<=xlen; ++i) {
      for(int j=1; j<=ylen; ++j) {
        if(X[i] == Y[j]) {
          C[i][j] = C[i-1][j-1] + 1;
        } else {
          C[i][j] = std::max(C[i-1][j], C[i][j-1]);
          
        }
      }
    }

    answers[m] = C[xlen][ylen];
  }

  for(int h=0; h<n; ++h) {
    std::cout << answers[h] << std::endl;
  }
}

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

constexpr int N=1000;

int lcs(string X, string Y){
   int c[N+1][N+1];
   int m=X.size();
   int n=Y.size();
   int maxl=0;

   //c[i][j]のためにX[0],Y[0]に空白を挿入
   X=' '+X;
   Y=' '+Y;
   for(int i=1; i<m+1; i++) c[i][0]=0;
   for(int j=1; j<n+1; j++) c[0][j]=0;

   for(int i=1; i<m+1; i++){
      for(int j=1; j<n+1; 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;
}

int main(){
   string x, y;
   int n; cin >> n;
   for(int i=0; i<n; i++){
      cin >> x;
      cin >> y;
      cout << lcs(x, y) << endl;
   }

   return 0;
}

C++: #include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX 150
#define L 1000

int LCSLength(char *X, char *Y){
  int m = strlen(X), n = strlen(Y);
  int i,j;
  int c[m+1][n+1];

  for(i=1; i<=m; i++) c[i][0] = 0;
  for(j=0; j<=n; j++) c[0][j] = 0;

  for(i=1; i<m+1; i++){
    for(j=1; j<n+1; j++){
      if(X[i-1] == Y[j-1]){
	c[i][j] = c[i-1][j-1] + 1;
      }
      else if(c[i-1][j] >= c[i][j-1]){
	c[i][j] = c[i-1][j];
      }
      else {
	c[i][j] = c[i][j-1];
      }
    }
  }

  return c[i-1][j-1];
}

int main(void){
  int q,i,j;
  int LCS[MAX];
  char X[MAX][L], Y[MAX][L];

  // input & calculate
  scanf("%d",&q);
  for(i=0; i<q; i++){
    scanf("%s", &X[i]);
    scanf("%s", &Y[i]);
    LCS[i] = LCSLength(X[i],Y[i]);
  }

  // output
  for(i=0; i<q; i++) printf("%d\n", LCS[i]);

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n); i >= 0; i--)
#define REP(i, m, n) for (int i = (int)(m); i <= (int)(n); i++)
#define REPR(i, m, n) for (int i = (int)(m); i >= (int)(n); i--)
#define all(v) v.begin(), v.end()
typedef long long ll;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

const long long INF = 1LL << 60;

int q;
int dp[1100][1100];

int main(){
  cin >> q;
  rep(k, q){
    string x, y;
    cin >> x >> y;
    int n = x.size();
    int m = y.size();

    memset(dp, 0, sizeof(dp));
    rep(i, n){
      rep(j, m){
        if(x[i] == y[j]) chmax(dp[i+1][j+1], dp[i][j]+1);
        else{
          chmax(dp[i+1][j+1], dp[i][j+1]);
          chmax(dp[i+1][j+1], dp[i+1][j]);
        }
      }
    }

    cout << dp[n][m] << endl;
  }

  return 0;
}

C++: #include <iostream>
#include <cmath>
#include <vector>

constexpr int MAX = 1000;
char ls[MAX];
char rs[MAX];
int table[MAX + 1][MAX + 1];


void calc_lcs() {
    scanf("%s", ls);
    scanf("%s", rs);
    int l_len = int(strlen(ls));
    int r_len = int(strlen(rs));
    for (int i = 0; i < l_len; i++) {
        table[i][0] = 0;
    }
    for (int i = 0; i < r_len; i++) {
        table[0][i] = 0;
    }

    for (int l_i = 1; l_i < l_len + 1; l_i++) {
        for (int r_i = 1; r_i < r_len + 1; r_i++) {
            if (ls[l_i - 1] == rs[r_i - 1]) {
                table[l_i][r_i] = table[l_i - 1][r_i - 1] + 1;
            } else {
                table[l_i][r_i] = std::max(table[l_i][r_i - 1], table[l_i - 1][r_i]);
            }
        }
    }
    std::cout << table[l_len][r_len] << std::endl;
}

int main() {
    int N;
    scanf("%d", &N);
    for (int i = 0; i < N; i++) {
        calc_lcs();
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define r(i,n) for(auto i=0;i<n;i++)
#define s(c) static_cast<int>((c).size())

int dp[1002][1002];

int main(){
	int n;
	cin >> n;
	int x, y;
	string X, Y;
	r(k, n){
		cin >> X >> Y;
		x = X.size();
		y = Y.size();
		X = ' ' + X;
		Y = ' ' + Y;

		r(i, x+1)
			r(j, y+1)
				dp[i][j] = 0;

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

		cout << dp[x][y] << endl;
	}
	return 0;
}