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 <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 = 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 (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 <vector>
#include <string>
using namespace std;

int lcs(string x, string y)
{
    int m = x.length();
    int n = y.length();
    int array[m + 1][n + 1];
    for (int i = 0; i <= m; i++)
    {
        array[i][0] = 0;
    }
    for (int i = 0; i <= n; i++)
    {
        array[0][i] = 0;
    }
    int lcsValue = 0;
    for (int i = 1; i <= m; i++)
    {
        for (int j = 1; j <= n; j++)
        {
            if (x[i - 1] == y[j - 1])
            {
                array[i][j] = array[i - 1][j - 1] + 1;
                lcsValue = max(lcsValue, array[i][j]);
            }
            else if (array[i - 1][j] >= array[i][j - 1])
            {
                array[i][j] = array[i - 1][j];
            }
            else
            {
                array[i][j] = array[i][j - 1];
            }
        }
    }
    return lcsValue;
}

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

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
using LL = long long;
typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<long> VL;

int lcs(string x, string y) {
  // 二次元配列の初期化
  vector<vector<int>> memo(x.size()+1, vector<int>(y.size()+1));
  for (int i=1; i<x.size()+1; i++) {
    for (int j=1; j<y.size()+1; j++){
      if (x[i-1] == y[j-1]) {
        memo.at(i).at(j) = memo.at(i-1).at(j-1) + 1;
      } else {
        if (memo.at(i).at(j-1) > memo.at(i-1).at(j)) {
          memo.at(i).at(j) = memo.at(i).at(j-1);
        } else {
          memo.at(i).at(j)= memo.at(i-1).at(j);
        }
      }
    }
  }
  return memo.at(x.size()).at(y.size());
}

int main() {
  int n; cin >> n;
  rep(i, n) {
    string x, y; cin >> x >> y;
    cout << lcs(x, y) << endl;
  }
}

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

static const int N = 1000;

int lcs(string X,string Y){
    int c[N+1][N+1];    //c[i][k]???Xi??¨Yk???LCS??¨??????????????????
    int m = X.size();
    int n = Y.size();
    int maxl = 0;
    X = ' ' + X; // X[0]?????????????????\
    Y = ' ' + Y;
    for(int i=1;i<=m;i++) c[i][0] = 0;
    for(int k=1;k<=n;k++) c[0][k] = 0;

    for(int i=1;i<=m;i++){
        for(int k=1;k<=m;k++){
            if(X[i]==Y[k]){
                c[i][k] = c[i-1][k-1] + 1;
            } else {
                c[i][k] = max(c[i-1][k],c[i][k-1]);
            }
            maxl = max(maxl,c[i][k]);
        }
    }

    return maxl;
}

int main(){
    string s1,s2;
    int n; scanf("%d",&n);
    for(int i=0;i<n;i++){
        cin >> s1 >> s2;
        printf("%d\n",lcs(s1,s2));
    }

    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 res = 0;

    x = ' ' + x;
    y = ' ' + y;

    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 (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]);
            }
            res = max(res, c[i][j]);
        }
    }

    return 0;
}

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>
#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 = 0; 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>
#include <map>
#include <set>
#include <algorithm>
using namespace std;
#define MAX 100000

static const int N =100;

int lcs(string X,string Y){
  int C[N+1][N+1];
  int m=X.size();
  int n=Y.size();
  int ans=0;
  X= ' '+X;
  Y= ' '+Y;
  for(int i;i<=m;i++)c[i][0]=0;
  for(int j;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]);
      }
      ans=max(ans,c[i][j]);
    }
  
  }
  return ans;
}

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