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 <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

static const int N=1000;

int lcs(string X, string Y) {
   // lcs置き場
   int c[N+1][N+1];

   int m = X.size();
   int n = Y.size();
   int maxl = 0;
   X = ' ' + X;
   Y = ' ' + Y;
   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(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 n;cin>>n;
   rep(i, n) {
      string X, Y; cin>>X>>Y;
      cout << lcs(X, Y) << endl;
   }
   return 0;
}

C++: #include "iostream"
#include "string.h"

using namespace std;

int L[1001][1001];

int lcs( char s1[], char s2[], int l1, int l2 ) {

	if (L[l1][l2] != 0)return L[l1][l2];

	if (l1 == 0 || l2 == 0) return 0;
	else if (s1[l1-1] == s2[l2-1]) L[l1][l2] = lcs(s1, s2, l1 - 1, l2 - 1) + 1;
	else {
		int lsc1 = lcs(s1, s2, l1 - 1, l2);
		int lsc2 = lcs(s1, s2, l1, l2 - 1);

		if (lsc1 > lsc2) L[l1][l2] = lsc1;
		else L[l1][l2] = lsc2;
	}

	return L[l1][l2];
}

int main() {

	int n;
	char s1[1000], s2[1000];

	cin >> n;

	int ans[150];

	for (int i = 0; i < n; i++) {
		cin >> s1;
		cin >> s2;

		ans[i] = lcs(s1, s2, strlen(s1), strlen(s2));
	}

	for (int i = 0; i < n; i++) {
		cout << lcs(s1, s2, strlen(s1), strlen(s2)) << endl;
	}

	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using pii = pair<int, int>;

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;
}

int main() {
	int q;
	cin >> q;
	while (q--) {
		string x, y;
		cin >> x >> y;
		int xsz = x.size();
		int ysz = y.size();
		//vector<vector<int>> dp(xsz + 1, vector<int>(ysz + 1));
	    int dp[1001][1001] = { 0 };
		for (int i = 0; i < xsz; i++) {
			for (int j = 0; j < ysz; j++) {
				if (x[i] == y[j]) chmax(dp[i + 1][j + 1], dp[i][j] + 1);
				chmax(dp[i + 1][j + 1], dp[i][j + 1]);
				chmax(dp[i + 1][j + 1], dp[i + 1][j]);
			}
		}
		cout << dp[xsz][ysz] << endl;
	}
	return 0;
}

C++: #include<stdio.h>
#include<string.h>
int t[1002][1002];
char s[1002],st[1002],q;
int maxn(int a,int b){
return a > b ? a : b;
}

void scan(char *a , char *b){
int l = strlen(a) , r = strlen(b);
for(int i = 0 ; i < l ; i ++ ){
    for(int j = 0 ; j < r ; j ++ )
    {
        if(a[i] == b[j])t[i+1][j+1] = 1;
    }
}
}

int prin(char *a , char *b){
int l = strlen(a) , r = strlen(b);
for(int i = 1 ; i <= l ; i ++ ){
    for(int j = 1 ; j <= r ; j ++ )
    {
        if(a[i] == b[j])t[i][j] = t[i-1][j-1]+1;
        else t[i][j] = maxn(t[i-1][j],t[i][j-1]);
    }
}
return t[l][r];
}

int main(){
int n ;
scanf("%d%c",&n,&q);
while(n--){
    scanf("%s%c%s",s,&q,st);
    scan(s,st);
    printf("%d\n",prin(s,st));
}
return 0;
}

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

#define REP(i, n) for(int (i) = 0; (i) < (n); (i)++)

string str1, str2;
int dp[1001][1001];
int k;

int solve(int i, int j)
{
  if(dp[i][j] > 0)
    return dp[i][j];
  if(i >= str1.size() || j >= str2.size()){
    if(i < str1.size()){
      return solve(i + 1, k);
    }else{
      return 0;
    }
  }
  if(str1[i] == str2[j]){
    k = j + 1;
    int n, m = 0;
    for(int l = i + 1; l < str1.size(); l++){
      n = solve(l, j + 1);
      m = (n > m) ? n : m;
    }
    dp[i][j] = m + 1;
    return dp[i][j];
  }else{
    return solve(i, j + 1);
  }
}
  
int main()
{
  int q, n, ans = 0;
  cin >> q;
  cin.ignore();
  REP(i, q){
    getline(cin, str1);
    getline(cin, str2);
    if(str1.size() < str2.size())
      swap(str1, str2);
    fill(&dp[0][0], &dp[1001][0], -1);
    REP(j, str1.size()){
      n = solve(j, 0);
      ans = (n > ans) ? n : ans;
    }
    cout << ans << endl;
    ans = 0;
  }
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rrep(i, n) for (int i = (n - 1); i >= 0; i--)
#define ALL(v) v.begin(), v.end()
using namespace std;
using P = pair<int, int>;
typedef long long ll;

void solve() {
  string s, t;
  cin >> s >> t;
  int n = s.size();
  int m = t.size();
  vector<vector<int>> dp(n+1, vector<int>(m+1, 0));
  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+1][j], dp[i][j+1]);
      }
    }
  }
  cout << dp[n][m] << "\n";
}

int main() {
  int q;
  cin >> q;
  rep(i, q)solve();
  return 0;
}

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

// int c[1000][1000];

int lcs(string x, string y){
  int m = x.size();
  int n = y.size();

  int c[1001][1001];
  for(int i=1;i<=m;i++) c[i][0] = 0;
  for(int j=1;j<=n;j++) c[0][j] = 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;
  cin >> q;
  string s1, s2;
  for(int i=0;i<q;i++){
    cin >> s1 >> s2;
    cout << lcs(s1, s2) << endl;
  }
  return 0;
}