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 <vector>
#include <string>
#include <algorithm>

using namespace std;

int lcs(string a, string b)
{
	vector<vector<int> > dp(1001, vector<int>(1001));
	for (int i = 0; i < a.size(); ++i)
	{
		for (int j = 0; j < b.size(); ++j)
		{
			if (a[i] == b[j])
			{
				dp[i + 1][j + 1] = dp[i][j] + 1;
			}
			else
			{
				dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1]);
			}
		}
	}
	return(dp[a.size()][b.size()]);
}

void solve()
{
	int q;
	cin >> q;
	for (int i = 0; i < q; ++i)
	{
		string a, b;
		cin >> a >> b;
		cout << lcs(a, b) << endl;
	}
}

int main()
{
	solve();
	return(0);
}

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

using namespace std;

int LCS(string X, string Y) {

	int lcs[X.size() + 1][Y.size() + 1];

	for (int i = 0; i < X.size(); ++i) {
		lcs[0][i] = 0;
	}
	for (int i = 0; i < Y.size(); ++i) {
		lcs[i][0] = 0;
	}

	for (int i = 1; i <= X.size(); ++i) {
		for (int j = 1; j <= Y.size(); ++j) {
			if (X[i - 1] == Y[j - 1]) {
				lcs[i][j] = lcs[i - 1][j - 1] + 1;
			} else if (lcs[i - 1][j] > lcs[i][j - 1]) {
				lcs[i][j] = lcs[i - 1][j];
			} else {
				lcs[i][j] = lcs[i][j - 1];
			}
		}
	}

	return lcs[X.size()][Y.size()];
}

int main() {

	int q;
	scanf("%d", &q);

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

	return 0;

}

C++: #include <iostream>
#include <string>
#include <array>

using namespace std;


int solve(const string& s1, const string& s2) {
    const size_t N = 1000 + 1;
    int A[N][N] = {0};

    auto m = s1.size();
    auto n = s2.size();
    for (int i = 1; i <= m; ++i) {
        for (int j = 1; j <= n; ++j) {
            if (s1[i-1] == s2[j-1]) {
                A[i][j] = A[i-1][j-1] + 1;
            } else {
                A[i][j] = max(A[i][j-1], A[i-1][j]);
            }
        }
    }
    return A[m][n];
}

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

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

    return 0;
}

C++: #include<iostream>
#include<string>

using namespace std;

#if 0

以下のURLを参照。参照した箇所は、a = ' ' + a;のように空白をいれていることで文字のサイズを合わせていることである。
http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=2065462#1

サンプルインプットでは正しい出力を得られているようにみられているが、なぜかwrong answerが出力されてしまう。
#endif

int n;
string a, b;



int main(){
  cin >> n;
  while(n != 0){
    n = n -1;
    int longest[1051][1051];
    cin >> a;
    cin >> b;
    //a = ' ' + a;
    //b = ' ' + b;
    for(int i = 0; i <= a.size(); ++i){
      for(int j = 0; j <= b.size(); ++j){
        if(j <= 0 || i <= 0){
          longest[i][j] = 0;
        }
        else if(a[i] == b[j]){
          longest[i][j] = 1 + longest[i-1][j - 1];
        }
        else{
          longest[i][j] = max(longest[i][j-1], longest[i-1][j]);
        }
        
      }
    }
    //cout << a[1] << endl;
    cout << longest[a.size()][b.size()] << endl;
  }
}

C++: #include <cstdio>
#include <cstdlib>
#include <string>
#include <iostream>

using namespace std;
static const int N=1000;
int lcs(string X, string Y){
    int m=X.size();
    int n=Y.size();
    int c[N+1][N+1];
    int maxl=0;
    X=' '+X;
    Y=' '+Y;
    int i,j;
    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]);
            }
            maxl=max(maxl,c[i][j]);
        }
    }
    return maxl;
}
int main()
{
    int n;
    string s1,s2;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>s1>>s2;
        cout<<lcs(s1,s2)<<endl;
    }

    return 0;
}

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


int main()
{
    int q;
    cin >> q;
    for(int i = 0; i < q; i++){
        string x, y;
        cin >> x >> y;
        int c[1001][1001];
        for(int j = 0; j <= (int)x.size(); j++) c[j][0] = 0;
        for(int j = 0; j <= (int)y.size(); j++) c[0][j] = 0;
        for(int j = 1; j <= (int)x.size(); j++){
            for(int k = 1; k <= (int)y.size(); k++){
                if(x[j - 1] == y[k - 1]) c[j][k] = c[j - 1][k - 1] + 1;
                else c[j][k] = max(c[j - 1][k],c[j][k - 1]);
                
            
            }
        
        }
        cout << c[x.size()][y.size()] << endl;
        
        
        
    }
    
    
    return 0;
}

C++: #include <iostream>
#include <string>
#include <cstdio>
#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 maxl = 0;
  x = ' ' + x;
  y = ' ' + y;
  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 q;
  cin >> q;

  for ( int i = 0; i < q; 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], maxl = 0, i, j;
  int m = x.size();
  int n = y.size();

  x = ' ' + x;
  y = ' ' + y;
 
  for(i = 1; i <= m; i++) c[i][0] = 0;
  for(i = 0; i <= n; i++) c[0][i] = 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 - 1][j], c[i][j - 1]);
      }
      maxl = max(maxl, c[i][j]);
    }
  }
  return maxl;
}

int main(){
  string x, y;
  int q, i;

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

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

int lcs(string X, string Y) {
    int c[1001][1001];
    int m = X.size();
    int n = Y.size();
    X = ' ' + X;
    Y = ' ' + Y;
    int maxl = 0;
    for (int i = 0; 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 s1, s2;
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> s1 >> s2;
        cout << lcs(s1, s2) << endl;
    }
    return 0;
}