Go: package main

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

type Position struct {
	X int
	Y int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}
	for i := 0; i < n; i++ {
		strX := nextText(sc)
		strY := nextText(sc)
		fmt.Println(calcLcs(strX, strY))
	}
}

func calcLcs(strX, strY string) int {
	return lcs(strX, strY, Position{0, 0}, make(map[Position]int))
}

func lcs(strX string, strY string, position Position, memo map[Position]int) int {
	if position.X >= len(strX) || position.Y >= len(strY) {
		return 0
	}
	if v, ok := memo[position]; ok {
		return v
	}
	if strX[position.X] == strY[position.Y] {
		result := lcs(strX, strY, Position{position.X + 1, position.Y + 1}, memo)
		memo[position] = result + 1
		return memo[position]
	} else {
		result1 := lcs(strX, strY, Position{position.X + 1, position.Y}, memo)
		result2 := lcs(strX, strY, Position{position.X, position.Y + 1}, memo)
		var result int
		if result1 > result2 {
			result = result1
		} else {
			result = result2
		}
		memo[position] = result
		return result
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include <cstdio>
#include <algorithm>
#include <string>

using namespace std;
const int N_MAX = 1000;
char x[N_MAX+10], y[N_MAX+10];
int dp[N_MAX][N_MAX];

void solve() {
  int i, j;
  scanf("%s", x);
  scanf("%s", y);
  int N = strlen(x);
  int M = strlen(y);
  //printf("N = %d M = %d", N, M);
  for (i = 0; i < N+1; i++) {
    dp[i][0] = 0;
  }
  for (j = 0; j < M+1; j++) {
    dp[0][j] = 0;
  }
  for (i = 0; i < N; i++) {
    for (j = 0; j < M; j++) {
      if (x[i] == y[j]) {
	dp[i+1][j+1] = dp[i][j]+1;
      } else {
	dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
      }
    }
  }
  printf("%d\n", dp[N][M]);
} 

int main() {
  int q;
  scanf("%d", &q);
  for (int i = 0; i < q; i++) {
    solve();
  }
  return 0;
}

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

int dp[2000][2000];

int main(void){
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n; cin >> n;
  while(n--){
    string sa, sb; cin >> sa >> sb;
    memset(dp, 0, sizeof(dp));
    for(int i = 1; i <= sa.size(); i++){
      for(int j = 1; j <= sb.size(); j++){
        if(sa[i] == sb[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[sa.size()][sb.size()] << endl;
  }
  return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <algorithm>

using namespace std;

short checkTable[1001][1001];

int tmp_max=0;


void calc(int index,char pattern[],char to_search[],int to_search_length){

	for(int i=to_search_length-1;i>=0;i--){
		if(to_search[i]==pattern[index]){
			checkTable[index][i]=1;
			if(pattern[index+1]!='\0' && i < to_search_length-1){
				checkTable[index][i] = checkTable[index+1][i+1] + checkTable[index][i];
			}
		}else{
			if(i != to_search_length-1){
				if(pattern[index+1] != '\0'){
					checkTable[index][i]=(checkTable[index+1][i]>checkTable[index][i+1])
							?checkTable[index+1][i]:checkTable[index][i+1];

				}else{
					checkTable[index][i]=(checkTable[index][i+1]>0)?checkTable[index][i+1]:0;
				}
			}else{
				if(pattern[index+1] != '\0'){
					checkTable[index][i]=(checkTable[index+1][i]>0)?checkTable[index+1][i]:0;
				}else{
					checkTable[index][i] = 0;
				}
			}
		}
		tmp_max = (tmp_max >= checkTable[index][i])?tmp_max:checkTable[index][i];
	}
}

int main(){

	int q,left_length,right_length;
	char left[1001],right[1001];

	scanf("%d",&q);

	for(int i=0;i<q;i++){
		left_length=0;
		right_length=0;
		scanf("%s %s",left,right);
		for(int k=0;left[k]!='\0';k++)left_length++;
		for(int k=0;right[k]!='\0';k++)right_length++;

		if(right_length>=left_length){

			for(int k=left_length-1;k>=0;k--)calc(k,left,right,right_length);
		}else{

			for(int k=right_length-1;k>=0;k--)calc(k,right,left,left_length);
		}
		printf("%d\n",tmp_max);
		tmp_max=0;
	}

    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 j=0; j<MAX; ++j) C[k][j] = 0;
    }

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

    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;
static const 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;
	X = ' ' + X;
	Y = ' ' + Y;
	for (int i = 1; i <= m; i++)c[i][0] = 0;
	for (int j = 1; j <= n; j++)c[0][j] = 0;

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

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

		return 0;
	}

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;
}