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] = dp[i-1][j-1]+1
				} else if S[i-1] != T[j-1] && dp[i-1][j] > dp[i][j-1] {
					dp[i][j] = dp[i-1][j]
				} else {
					dp[i][j] = dp[i][j-1]
				}
				// 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 <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <bitset>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
using namespace std;
typedef long long ll;
typedef pair<int,int> pint;
typedef vector<int> vint;
typedef vector<pint> vpint;
#define mp make_pair
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
int dx[4] = {1, 0, 0, -1};
int dy[4] = {0, 1, -1, 0};

void slove(string X, string Y){
	int dp[1000][1000];//dp[X?????????][Y?????????] = LCS
	int sizex = X.size();
	int sizey = Y.size();

	//???????????????????????????????????????????????????0????????????????????\?????????
	X = ' ' + X;
	Y = ' ' + Y;

	reps(i, 1, sizex + 1) dp[i][0] = 0;//?????????????????????0??????dp???0
	reps(i, 1, sizey + 1) dp[0][i] = 0;//?????????????????????0??????dp???0

	int ans = 0;//????°??????????
	reps(i, 1, sizex + 1){
		reps(j, 1, sizey + 1){
			if(X[i] == Y[j]) dp[i][j] = dp[i - 1][j - 1] + 1;
			else if(X[i] != Y[j]) dp[i][j] = max(dp[i][j - 1], dp[i - 1][j]);

			ans = max(ans, dp[i][j]);
		}
	}
	printf("%d\n", ans);
	return;
}

int main(void){
	int n; cin >> n;
	string s1, s2;
	rep(i, n){
		cin >> s1 >> s2;
		slove(s1, s2);
	}
	return 0;
}

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

using namespace std;
int LCS(const char* a,const char* b)
{
    int m=strlen(a); int n=strlen(b); //i???????¬????a????????????j???????¬????b?????????
    int c[m+1][n+1]; //c??°???????????¨?????°???????¬????a??????i??????????¬????b??????j????????´???LCS
    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=0;i<m;i++)
        for(int j=0;j<n;j++)
        {
            if(a[i]==b[j]) c[i+1][j+1]=c[i][j]+1;
            else
            {
                c[i+1][j+1]=max(c[i][j+1],c[i+1][j]);
            }
        }
    return c[m][n];

}
int main()
{
    char *a=new char[1001];
    char *b=new char[1001];
    int q;
    while(cin>>q)
    {
        for(int i=0;i<q;i++)
        {
            cin>>a>>b;
            cout<<LCS(a,b)<<endl;
        }
    }
}

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

int Ics(string X, string Y) {
	int c[101][101];
	int m = X.length();
	int n = Y.length();
	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 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() {
	int n;
	string x, y;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> x >> y;

		cout << Ics(x, y) << endl;
	}

	
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define MM 1000000000
#define MOD MM+7
#define MAX 301000
#define MAP 110
#define initial_value -1
#define Pair pair<int,int>
#define chmax(a,b) (a<b ? a=b:0)
#define chmin(a,b) (a>b ? a=b:0)
ll INF = 1e18;
int dx[4] = {-1,0,1,0};
int dy[4] = {0,-1,0,1};
//union_find
int par[100];
int depth[100];
ll N;
ll x[20],c[20],v[20];
string s,t;

int lcs(string x, string y){
    int dp[1010][1010];
    int m = x.size();
    int n = y.size();
    int mx = 0;
    x = ' ' + x;
    y = ' ' + y;
    for(int i = 0; i <= m; i++) dp[i][0] = 0;
    for(int i = 1; i <= n; i++) dp[0][i] = 0;
    for(int i = 1; i <= m; i++){
        for(int j = 1; j <= n; j++){
            if(x[i] == y[i]){
                dp[i][j] = dp[i-1][j-1] + 1;
            } else {
                dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            }
            mx = max(mx, dp[i][j]);
        }
    }
    return mx;
}
int main(){
    cin >> N;
    for(int i = 0; i < N; i++){
        cin >> s >> t;
        cout << lcs(s,t) << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

int main() {

    int n;
    string str1, str2;

    cin >> n;

    for(int cnt = 0; cnt < n; ++cnt) {

        cin >> str1 >> str2;

        int dp[str1.size() + 1][str2.size() + 1];

        for(int i = 0; i <= str1.size(); ++i) {
            dp[i][0] = 0;
        }

        for(int i = 0; i <= str2.size(); ++i) {
            dp[0][i] = 0;
        }

        for(int i = 1; i <= str1.size(); ++i) {
            for(int j = 1; j <= str2.size(); ++j) {
                if(str1[i - 1] == str2[j - 1]) {
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                } else {
                    dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
                }
            }
        }

        cout << dp[str1.size()][str2.size()] << endl;

    }

}