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>
int main(){
  int q;
  std::cin>>q;
  int i,j,k;
  std::string x,y;
  int a[1001][1001];
  int knum[q];
  for(i=0; i<1001; i++){
    for(j=0; j<1001; j++){
      a[i][j]=0;
    }
  }
  for(k=0; k<q; k++){
    std::cin>>x;
    std::cin>>y;
    for(i=1; i<x.size()+1; i++){
      for(j=1; j<y.size()+1; j++){
	if(x[i-1]==y[j-1]){
	  a[i][j]=a[i-1][j-1]+1;
	}else{
	  if(a[i-1][j]>a[i][j-1]){
	    a[i][j]=a[i-1][j];
	  }else{
	    a[i][j]=a[i][j-1];
	  }
	}
      }	
    }
    knum[k]=a[x.size()][y.size()];
  }
  for(k=0; k<q; k++){
    std::cout<<knum[k]<<"\n";
  }
  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 = 1; 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 <bits/stdc++.h>
using namespace std;
typedef long long ll;
//template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
//template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
 
/* attention
    long longのシフト演算には気をつけよう
    タイポした時のデバッグが死ぬほどきつくなるので変数名は最低3字くらい使った方がいいかも
*/

int lcm(string s, string t, vector<vector<int>> dp){
    int m = s.size();
    int n = t.size();
    int maxl = 0;
    s = " " + s;
    t = " " + t;
    for(int i=0; i<=m; i++) dp[i][0] = 0;
    for(int j=0; j<=n; j++) dp[0][j] = 0;

    for(int i=1; i<=m; i++){
        for(int j=1; j<=n; j++){
            if(s[i] == t[j]) dp[i][j] = dp[i-1][j-1]+1;
            else dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            maxl = max(maxl, dp[i][j]);
        }
    }

    return maxl;
}

int main(){
    vector<vector<int>> dp(1001, vector<int>(1001, 0));

    int n; cin >> n;
    for(int i=0; i<n; i++){
        string s, t; cin >> s >> t;
        cout << lcm(s, t, dp) << 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>
#include<algorithm>
using namespace std;

int lcs(string str1, string str2) {
	int n1 = str1.size();
	int n2 = str2.size();
	int A[n1 + 1][n2 + 1];
	for (int i = 0; i <= n1; i++) A[i][0] = 0;
	for (int j = 1; j <= n1; j++) A[0][j] = 0;

	for (int i = 1; i <= n1; i++) {
		for (int j = 1; j <= n2; j++) { 
			if (str1[i - 1] == str2[j - 1]) {
				A[i][j] = A[i - 1][j - 1] + 1; 
			} else {
				A[i][j] = max(A[i - 1][j], A[i][j - 1]); 
			}
		}
	}
	return A[n1][n2];
}

int main() {
	int n;
	string str1, str2;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> str1 >> str2;
		cout << lcs(str1, str2) << endl;
	}
	return 0;
}