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<stdio.h>
//#include<cstdlib>
#include<cstring>

#define MAX_LEN 1000

int c[MAX_LEN+1][MAX_LEN+1]; // length of longest common subsequence

void p(){
    printf("\ntest\n");
}

int max(int a, int b){
    return a > b ? a : b;
}

int LCS(char *s1, char *s2){
    int i, j,   l, m;
    l = strlen(s1);
    m = strlen(s2);
    //printf("l:%d m:%d", l, m);
    
    for (i = 0; i < l; i++) {
        c[i][0] = 0;
     }
    
    for (j = 0; j < m; j++) {
        c[0][j] = 0;
    }
    
    
    for (i = 1; i < l+1; i++) {
        for (j = 1; j < m+1; j++) {
            if (s1[i-1] == s2[j-1]) {
                c[i][j] = c[i-1][j-1] + 1;
            }else{
                c[i][j] = max(c[i][j-1], c[i-1][j]);
            }
            //printf("c[%d][%d]:%d\n", i, j, c[i][j]);
        }
    }
    
    
    return c[l][m];
}

int main(){
    int i, n;
    char s1[MAX_LEN+1], s2[MAX_LEN+1];
    
    scanf("%d", &n);
    for (i = 0; i < n; i++) {
        scanf(" %s", s1);
        scanf(" %s", s2);
        //printf("%s\n%s\n", s1, s2);
        printf("%d\n", LCS(s1, s2));
    }
    
    return 0;
}

C++: #include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
int p[1001][1001]={0};
int main(){
int i,j,q,e,l,z,m,u,n;
char s[2001],c[2001];
cin>>q;
for(e=0;e<q;e++){
scanf("%s %s",s,c);
l=strlen(s);
z=strlen(c);

for(i=0;i<=l;i++){
	for(j=0;j<=z;j++){
		p[i][j]=0;
	}
}
n=0;
for(i=1;i<=z;i++){
	for(j=1;j<=l;j++){
		if(c[i-1]==s[j-1])p[j][i]=p[j-1][i-1]+1;
		else p[j][i]=p[j][i-1];
	}
}
cout<<p[l][z]<<endl;
}
return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using lint = int64_t;
#define rep(i, n) for(int i=0; i<(n); ++i)
#define all(v)    begin(v), end(v)
#define in        []{lint n; cin>>n; return n;}()


#define LCS longest_common_subsequence
int longest_common_subsequence( const string S, const string T ) {
    vector<vector<int>> dp( S.size()+1, vector<int>(T.size()+1, 0) );

    rep( s, S.size() ) {
    rep( t, T.size() ) {
        dp[s+1][t+1] = S[s] == T[t] ?
            dp[s][t] + 1 :
            max( dp[s][t+1], dp[s+1][t] );
    }
    }

    return dp[S.size()][T.size()];
}

int main() { cin.tie(0); ios::sync_with_stdio(false);
    int N = in;
    rep( _, N ) {
        string S, T; cin >> S >> T;
        cout << LCS( S, T ) << "\n";
    }
}

C++: #include <iostream>
#include <climits>
#include <string>
using namespace std;
const int MAXSEQ = 1000;
const int INFY = -INT_MAX;

string X, Y;

int max(int m, int n){
    int max = INFY;
    printf("\n");
    return max;
}
int LSCLength(void){
    int m = X.size();
    int n = Y.size();
    int c[m+1][n+1];
    for (int i = 0; i <= m; i++){
        c[i][0] = 0;
    }
    for (int j = 0; j <= n; j++){
        c[0][j] = 0;
    }
    /*
    for (int i = 0; i <= m; i++){
        for (int j = 0; j <= m; j++){
        */
    /*
    if (m > n){
        cout << "will change X =" <<  X << endl;
        swap(m, n);
        swap(X, Y);
        cout << "changed X =" <<  X << endl;
    }*/
    for (int i = 1; i <= m; i++){
        for (int j = 1; j <= n; j++){
            if (X[i-1] == Y[j-1]){
                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];
            }
        }
    }
    int max = INFY;
    //printf("\n");
    /*
    for (int i = 0; i <= m; i++){
        for (int j = 0; j <= n; j++){
            printf("%d ", c[i][j]);
        if (max < c[m][i]) max = c[i][j];
        }
        printf("\n");
    }
    */
    for (int j = 1; j <= n; j++){
        if (max < c[m][j]) max = c[m][j];
    }
    return max;
}

int main(int argc, char* argv[]) {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++){
        cin >> X >> Y;
        cout << LSCLength() << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define FOR(I,A,B) for(ll I = (A); I < (B); ++I)
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin()) //xi>=v
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin()) //xi>v
#define NUM(x,v) (POSU(x,v)-POSL(x,v))
const ll INF=1e9+7;
const ll N = 1002;
const ll M = 21;
ll q,dp[N][N];
string x,y;
vector <ll> ans;

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin>>q;
	FOR(k,0,q){
		cin>>x>>y;
		FOR(i,0,x.size()+1){
			FOR(j,0,y.size()+1){
				dp[i][j]=0;
			}
		}
		FOR(i,0,x.size()+1){
			FOR(j,0,y.size()+1){
				if(i==0||j==0)dp[i][j]=0;
				else{
					if(x[i]==y[j])dp[i][j] = max(dp[i-1][j]+1,dp[i][j-1]+1);
					else dp[i][j] = max(dp[i-1][j],dp[i][j-1]);
				} 
			}
		}
		ans.push_back(dp[x.size()][y.size()]);
	}
	FOR(i,0,ans.size()){
		cout<<ans[i]<<endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define INF 10000
using namespace std;

int main(){
  int N; cin>>N;
  for (int i =0; i<N; i++) {
    string s1,s2; cin >> s1 >> s2;
    int s1N = s1.size();
    int s2N = s2.size();
    int dp[s1N+1][s2N+1];
    
    for(int j=0; j<=s1N; j++) dp[j][0] =0;
    for(int k=0; k<=s2N; k++) dp[0][k] =0;
  
    for(int j=1; j<=s1N; j++){
      for(int k=1; k<=s2N; k++){ 
        if(s1[j-1] == s2[k-1]) {
          dp[j][k] = dp[j-1][k-1] +1;
        } else {
          dp[j][k] = max(dp[j][k-1], dp[j-1][k]);
        }
      }
    }
    cout << dp[s1N][s2N] <<endl; 
  }
}