Go: package main

import (
	"fmt"
	"os"
	"strconv"
	"bufio"
	"strings"
	"sort"
)

// define
var (
	sc = bufio.NewScanner(os.Stdin)
)

func bordersInt(in_map [][]int, invalid int) [][]int{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]int, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]int, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func bordersString(in_map [][]string, invalid string) [][]string{
	H, W := len(in_map), len(in_map[0])
	out_map := make([][]string, H+2)
	for h:=0; h<H+2; h++ {
		out_map[h] = make([]string, W+2)
		for w:=0; w<W+2; w++ {
			out_map[h][w] = invalid
		}
	}
	for h:=0; h<H; h++{
		for w:=0; w<W; w++{
			out_map[h+1][w+1] = in_map[h][w] 
		}
	}
	return out_map
}

func scanIntLine(len int) []int{
	arr := make([]int, len)
	for i:=0; i<len; i++{
		sc.Scan()
		tmp, err := strconv.Atoi(sc.Text())
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func scanStringLine(len int) []string{
	arr := make([]string, len)
	for i:=0; i<len; i++{
		sc.Scan()
		arr[i] = sc.Text()
	}
	return arr
}

func scanIntSplit(len int) []int{
	arr := make([]int, len)
	sc.Scan()
	for i, v := range strings.Split(sc.Text(), " "){
		tmp, err := strconv.Atoi(v)
		if err == nil{
			arr[i] = tmp
		}
	}
	return arr
}

func maxInt(args... int) int{
	sort.Ints(args)
	return args[len(args)-1]
}

func main(){
	buf := make([]byte, 0)
    sc.Buffer(buf, 1000000009)
	var n int 
	fmt.Scan(&n)
	dp := make([][]int, 1003)
	for i:=0; i<1003; i++ {
		dp[i] = make([]int, 1003)
	}
	input_lines := scanStringLine(2*n)
	for i:=0; i<n; i++ {
		S, T := input_lines[2*i], input_lines[2*i+1]
		lenS, lenT := len(S), len(T)
		for i:=1; i<lenS+1; i++ {
			for j:=1; j<lenT+1; j++ {
				if S[i-1] == T[j-1] {
					dp[i][j] = maxInt(dp[i-1][j-1]+1, dp[i-1][j], dp[i][j-1])
				} else {
					dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
				}
			}
		}
		fmt.Println(dp[lenS][lenT])
	}
}

C++: #include <iostream>
#include <sstream>
#include <vector>
#include <algorithm>
#include <string>
#include <functional>
#include <numeric>
#include <ctype.h>
#include <cstdlib>
#include <string.h>
#include <cmath>
#include <cstdio>
#include <map>
#include <queue>
#include <utility>
#define rep(i, n) for(int i = 0; i < n; i++);

using namespace std;

const int INF = 1000000007;
const double PI = acos(-1.0);
typedef long long llong;

const int N = 10000;

int search(string X, string Y)
{
	int c[1000 + 1][1000 + 1];
	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
				c[i][j] = max(c[i - 1][j], c[i][j - 1]);

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

	return maxl;
}



int main()
{
	string input1, input2;
	int n;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> input1 >> input2;
		cout << search(input1, input2) << endl;
	}

	return 0;
	

}

C++: #include <cmath>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <climits>
#include <map>
#include <list>
#include <stack>
#include <queue>
#include <vector>
#include <string>
#include <sstream>
#include <fstream>
#include <iostream>
#include <algorithm>
using namespace std;

int dat[1024][1024];
int getLcbLen(char* x, int xe, char* y, int ye){
	cout << xe << ":"<<ye<<endl;
	if(xe <= 0 || ye <= 0) return 0;
	if(dat[xe][ye] != -1) return dat[xe][ye];
	return dat[xe][ye] = (x[xe-1] == y[ye-1] ? 1 + getLcbLen(x, xe-1, y, ye-1) : max(getLcbLen(x, xe-1, y, ye), getLcbLen(x, xe, y, ye-1)));
}

int main() {
	int set;
	scanf("%d", &set);
	
	while(set--){
		char x[1024], y[1024];
		scanf("%s %s", x, y);
		int xe = (int)strlen(x), ye = (int)strlen(y);
		
		for(int i = 0; i < xe; i++){
			for(int k = 0; k < ye; k++){
				dat[i][k] = -1;
			}
		}
		printf("%d\n", getLcbLen(x, xe, y, ye));
	}
	return 0;
}

C++: #include<bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
typedef long long ll;
#define rep(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
#define REP(i,num,n) for(int i=num, i##_len=(n); i<i##_len; ++i)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
#define print(x) (cout << (x) << endl)
#define pb push_back
#define mp make_pair
#define sz(x) int(x.size())
template<class T> inline void Yes(T condition){ if(condition) cout << "Yes" << endl; else cout << "No" << endl; }
template<class itr> void cins(itr first, itr last){ for(auto i = first; i != last; i++){ cin >> (*i); } }
template<class itr> void array_output(itr start, itr goal){ string ans; for(auto i = start; i != goal; i++) ans += to_string(*i) + " "; if(!ans.empty()) ans.pop_back(); cout << ans << endl; }
#define fs first
#define sc second

const int INF = 1e9;
const ll LLINF = 1e16;
const ll MOD = 1e9+7;
template<class T> inline void add(T &a, T b){a = ((a+b) % MOD + MOD) % MOD;};

template<typename T>
vector<T> make_v(size_t a){return vector<T>(a);}
 
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts){
  return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}
 
template<typename T,typename U,typename... V>
typename enable_if<is_same<T, U>::value!=0>::type
fill_v(U &u,const V... v){u=U(v...);}
 
template<typename T,typename U,typename... V>
typename enable_if<is_same<T, U>::value==0>::type
fill_v(U &u,const V... v){
  for(auto &e:u) fill_v<T>(e,v...);
}
 

// 指定した文字cが文字列に何文字入ってるか
ll stringcount(string s, char c) {
    return count(s.cbegin(), s.cend(), c);
}


// 割り算の切り上げ処理
template<typename T>
T rp(T a, T b) {
  return (a + b - 1) / b;
}

// 桁和
template<typename T>
T digsum(T n) {
    T res = 0;
    while(n > 0) {
        res += n%10;
        n /= 10;
    }
    return res;
}

// 回文判定
bool kai (string s) {
    string t{s};
    reverse(begin(t), end(t));
    return s == t;
}

using pint = pair<int, int>;
using pll = pair<ll, ll>;

int main(void)
{
    cout.tie(0);
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    int q;
    cin >> q;
    rep(i ,q) {
        string s,s2;
        cin >> s >> s2;
        int dp[1100][1100] = {0};
        rep(i, sz(s)){
          rep(j, sz(s2)){
              if(s[i] == s2[j]) dp[i + 1][j + 1] = dp[i][j] + 1;
              chmax(dp[i + 1][j + 1], dp[i + 1][j]);
              chmax(dp[i + 1][j + 1], dp[i][j + 1]);
          }
        }
        print(dp[sz(s)][sz(s2)]);
    }
}

C++: #include <iostream>
#include <fstream>
#include <set>
#include <map>
#include <queue>
#include <vector>
#include <algorithm>
#include <cmath>
#include <chrono>

using namespace std;

int main(int argc, const char * argv[]) {
    
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int q; cin >> q;
    for (int m = 0; m < q; m++) {
        string s, t; cin >> s >> t;
        vector<vector<int>> dp(s.size() + 1, vector<int>(t.size() + 1, 0));
        
        for (int i = 0; i < s.size(); i++) {
            for (int j = 0; j < t.size(); j++) {
                if (s.at(i) == t.at(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]);
            }
        }
        
        cout << dp[s.size()][t.size()] << endl;
    }
    
    return 0;
}