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]
}

C++: #include<algorithm>
#include<iostream>
#include<cstring>
#define rep(i,a) for(int i=0;i<(a);++i)
#define repd(i,a) for(int i=(a);i>=0;--i)
#define clr(a,v) memset((a),(v),sizeof(a))

const int MAX_X = 1000, MAX_Y = 1000;

int q;
std::string X, Y;
int dp[MAX_X+1][MAX_Y+1];

int main()
{
    std::cin >> q;
    while( q-- )
    {
        std::cin >> X >> Y;

        clr( dp, 0 );

        repd( i, X.size()-1 ) repd( j, Y.size()-1 )
        {
            if( X[i] == Y[j] )
                dp[i][j] = dp[i+1][j+1]+1;
            else
                dp[i][j] = std::max( dp[i+1][j], dp[i][j+1] );
        }

        printf( "%d\n", dp[0][0] );
    }

    return 0;
}

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

#define MAX 1000

int lcs(string X, string Y) {
    int c[MAX+1][MAX+1];
    int m = X.size();
    int n = Y.size();
    int i, j;
    int maxlen = 0;
    X = " " + X;
    Y = " " + Y;

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

    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][j-1], c[i-1][j]);
            }
            maxlen = max(maxlen, c[i][j]);
        }
    }
    return maxlen;
}

int main (void) {
    int N, i;
    string x, y;

    cin >> N;

    for(i = 0 ; i < N ; i++) {
        cin >> x;
        cin >> y;
        printf("%d\n", lcs(x,y));
    }

    return 0;
}

C++: // LCSの練習

#include"bits/stdc++.h"
#include <iostream>
#include <vector>


using namespace std;


int main(){
	
	int q;

	cin >> q ;

	vector<int> ans;

	for(int i= 0; i < q; i++){
		
		string x,y;

		cin >> x;
		cin >> y;

		int len_x = (int)x.length();
		int len_y = (int)y.length();

		// int dp[len_x+1][len_y+1];

		vector<vector<int> > dp(len_x + 1, vector<int>(len_y + 1));

		for(int i = 1; i <= len_x; i++){
			for(int j = 1; j <= len_y; j++){
				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]); 
				}
			}
		}

		ans.push_back(dp[len_x][len_y]);
		// cout << dp[len_x][len_y] << endl;

	}

	for(int i = 0; i < q; i++){
		cout << ans[i] << endl;
	}

	return 0;
}

C++: #include <iostream>

int lcs(std::string x, std::string y)
{
  int m = x.length();
  int n = y.length();
  int cs[m + 1][n + 1];

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

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

  return cs[m][n];
}

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

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

  return 0;
}

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;  // X[0]に空白を挿入
  Y = ' ' + Y;  // X[0]に空白を挿入
  for (int i = 0; i <= m; i++) c[i][0] = 0;
  for (int j = 0; 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 s1, string s2) {
    int c[1005][1005];
    int m = s1.length();
    int n = s2.length();
    s1 = " " + s1;
    s2 = " " + s2;
    int max1 = 0;
    for (int i = 0; i <= m; i++) {
        c[i][0] = 0;
    }
    for (int i = 0; i <= n; i++) {
        c[0][i] = 0;
    }
    for (int i = 1; i <= m; i++) {
        for (int j = 1; j <= n; j++) {
            if (s1[i] == s2[j]) {
                c[i][j] = c[i - 1][j - 1] + 1;
            } else {
                c[i][j] = max(c[i - 1][j], c[i][j - 1]);
            }
            max1 = max(max1, c[i][j]);
        }
    }
    return max1;
}

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

    return 0;
}

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

int main(){
  int number;
  string x;
  string y;
  int L[100][100];
  cin >> number;
  while(cin >> x >> y){
    for(int i = 0; i <= x.length(); i++){
      for(int j = 0; j <= y.length(); j++){
        if(i <= 0 || j <= 0){
         L[i][j] = 0;
        }else if(x[i-1] == y[j-1]){
         L[i][j] = 1 + L[i-1][j-1];
        }else{
         L[i][j] = max(L[i][j-1], L[i-1][j]);
        }
     }
   }
   cout << L[x.length()][y.length()] << endl;
 }
}

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 #endif