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 <algorithm>
using namespace std;

int dp[1002][1002];

int lcs(string s1,string s2) {
    int m = s1.length();
    int n = s2.length();
    s1 = " " + s1;
    s2 = " " + s2;
    for(int i=1;i<=m;i++) dp[i][0] = 0;
    for(int i=1;i<=n;i++) dp[0][i] = 0;
    int rec = 0;
    for(int i=1;i<=m;i++) {
        for(int j=1;j<=n;j++) {
            if(s1[i] == s2[j]) {
                dp[i][j] = dp[i-1][j-1] + 1;
            } else {
                dp[i][j] = max(dp[i-1][j],dp[i][j-1]);
            }
            rec = max(rec,dp[i][j]);
        }
    }
    return rec;
}

int main() {
    int n; cin >> n;
    while(n--) {
        string s1,s2; cin >> s1 >> s2;
        cout << lcs(s1,s2) << endl;
    }
    return 0;
}

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

static const int max_n = 1000;
string s1, s2;
int q, c[max_n + 1][max_n + 1];

int lcs(string X, string Y){
	int m = X.size();
	int n = Y.size();
	int maxl = 0;
	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 if(c[i - 1][j] >= c[i][j - 1]){
				c[i][j] = c[i - 1][j];
			}
			else{
				c[i][j] = c[i][j - 1];
			}
			maxl = max(maxl, c[i][j]);
		}
	}
	return maxl;
}

int main(void){
	cin >> q;
	for( int i = 1; i <= q; i++ ){
		cin >> s1 >> s2;
		cout << lcs(s1, s2) << endl;
	}
	return 0;
}

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

#define MAX_N 1000
#define MAX_M 1000

//入力
int n;
string s, t;
//char s[MAX_N], t[MAX_M];

int dp[MAX_N + 1][MAX_M + 1]; //DPテーブル

void solve(){
	for(int i = 0; i < s.size(); i++){
		for(int j = 0; j < t.size(); j++){
			if(s[i] == t[j]){
				dp[i + 1][j + 1];
					dp[i + 1][j + 1] = dp[i][j] + 1;
				} else {
					dp[i + 1][j + 1] = max(dp[i][j], dp[i + 1][j]);
				}
			}
		}
		printf("%d\n", dp[s.size()][t.size()]);
}

int main(){
	cin >> n;
	for(int i = 0; i < n; i++){
		cin >> s >> t;
		solve();
	}
}

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

using namespace std;

static const int N = 1000;

int lcs(string str1, string str2)
{
	int c[N + 1][N + 1];
	int m = str1.size();
	int n = str2.size();
	int maxl = 0;
	str1 = ' ' + str1;
	str2 = ' ' + str2;

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

	for (int i = 1; i <= m; i++)
	{
		for (int j = 1; j <= n; j++)
		{
			if (str1[i] == str2[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 str1, str2;
	int n;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> str1 >> str2;
		cout << lcs(str1, str2) << endl;
	}
	return 0;
}

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

using namespace std;

int LCS(string X, string Y) {

	int m, n;
	m = X.size();
	n = Y.size();

	int c[m + 1][n + 1];

	for (int i = 0; i <= m; ++i) {
		c[i][0] = 0;
	}
	for (int i = 0; i <= n; ++i) {
		c[0][i] = 0;
	}

	X = ' ' + X;
	Y = ' ' + Y;

	int maxl = 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() {

	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 <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
using namespace std;
typedef pair<int,int> P;
typedef long long int ll;
#define dame { puts("-1"); return 0;}
#define yn {puts("Yes");}else{puts("No");}

const int MAX_N = 1100;
const int MAX_M = 1100;
int n, m;
string s, t;
int dp[MAX_N+1][MAX_M+1];

int main(){
    int q; cin >> q;
    
    rep(i,q){
        cin >> s >> t;
        n = s.size();
        m = t.size();
        rep(i,n){
            rep(j,m){
                if(s[i]==t[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]);
                }
            }
        }

        cout << dp[n][m] << endl;
    }

        
    return 0;
}