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<string>
#include<vector>
#include<algorithm>
using namespace std;

int main(){
  vector <vector<int> > dp;
  string x,y;
  int n;

  cin >> n;
  for(int times=0;times<n;times++){
    int ans =0;

    cin >> x >> y;
    dp.resize(y.size()+1);
    for(int i=0;i<=y.size();i++){
      dp[i].resize(x.size()+1);
    }

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

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

    cout << ans << endl;
  }
}

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

#define MAX 100

using namespace std;

int lcs(string s1, string s2) {
    int C[MAX+1][MAX+1];
    int m = s1.size();
    int n = s2.size();
    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 = 1; i <= m; ++i) {
        for (int j = 1; j <= n; ++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]);
            }
        }
    }

    return C[m][n];
}

int main() {
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; ++i) {
        string s1, s2;
        cin >> s1 >> s2;
        cout << lcs(s1, s2) << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxx = 1010;
int c[maxx][maxx];

int lcs(char s1[],char s2[]) {
	int m = strlen(s1), n = strlen(s2);
	for (int i = 1; i <= m; i++)
		c[i][0] = 0;
	for (int i = 1; i <= n; i++)
		c[0][i] = 0;

	int ans = 0;
	for (int i = 1; i <= m; i++) {
		for (int j = 1; j <= n; j++) {
			if (s1[i] == s2[j])
				c[i][j] = c[i - 1][j - 1] + 1;
			else
				c[i][j] = max(c[i - 1][j], c[i][j - 1]);
			ans = max(ans, c[i][j]);
		}
	}
	return ans;
}
int main()
{
	char s1[maxx], s2[maxx];
	int t;
	scanf("%d", &t);
	for (int i = 0; i < t; i++) {
		scanf("%s %s", s1, s2);
		printf("%d\n", lcs(s1, s2));
	}

	return 0;
}

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

static const int ra =1000;

int lcs(string A, string B){
  int ca[ra+1][ra+1];
  int mi =A.size();
  int ni = B.size();
  int most = 0;

  A = ' ' + A;
  B = ' '+B;

  for(int i=1;i<=mi;i++){
    ca[i][0]=0;
  }
  for(int j=0;j<=ni;j++){
    ca[0][j] = 0;
  }

  for(int i =1;i<=mi;i++){
    for(int j=1;j<=ni;j++){
      if(A[i] == B[j]){
	ca[i][j] = ca[i-1][j-1]+1;
      }
      else{
	ca[i][j] = max(ca[i-1][j],ca[i][j-1]);
      }
      most = max(most,ca[i][j]);
    }
  }
  return most;
}

int main(){
  string K1,K2;
  int num,i;
  cin >>num ;
  for(i=0;i<num;i++){
    cin >> K1 >> K2;
    cout << lcs(K1,K2) << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#define NIL -1
using namespace std;

int count(const string& X, int i, const string Y, int j,
          vector<vector<int> >& MEMO){
    if (i >= X.size() || j >= Y.size()) return 0;
    if (MEMO[i][j] != NIL) return MEMO[i][j];
    int next_X = count(X, i + 1, Y, j, MEMO);
    int j_next = Y.find(X[i], j);
    if (j_next == string::npos) return MEMO[i][j] = next_X;
    int saiyou = count(X, i + 1, Y, j_next + 1, MEMO) + 1;
    return MEMO[i][j] = max(saiyou, next_X);
}

int main(){
    int q;
    cin >> q;
    for (int i = 0; i < q; i++) {
        string X, Y;
        cin >> X >> Y;
        vector<vector<int> > MEMO(X.size(), vector<int>(Y.size(), NIL));
        cout << count(X, 0, Y, 0, MEMO) << endl;
    }
    return 0;
}

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

int main()
{
    int q;
    cin>>q;
    vector<int>ansvec(q);
    int count=0;
    while (count<q)
    {string x,y;
     cin >> x>>y;
     vector<vector<int>>dp(x.size()+1,vector<int>(y.size()+1));
     rep(i,x.size())
     {
         rep(j,y.size())
         {
             dp[i+1][j+1]= (x[i]==y[j]) ? dp[i][j]+1 : max(dp[i+1][j],dp[i][j+1]) ;
         }
     }
     ansvec[count]=dp[x.size()][y.size()];
     count++;
    }
    
    rep(i,q)
    {
        cout<<ansvec[i]<<endl;
    }
   
    return 0;
}

C++: #include <stdio.h>
#include <string.h>
#define rep(i, n) for(int i = 0; i < n; ++i)
#define repi(i, n) for(int i = 1; i < n; ++i)

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

int main(void) {
  int n;
  scanf("%d", &n);
  rep(i, n) {
    char x[1500], y[1500], h, w;
    scanf("%s", x);
    scanf("%s", y);
    h = strlen(x), w = strlen(y);
    int dp[h][w], len[w];
    rep(j, h) rep(k, w) dp[j][k] = 0;
    rep(j, w) if(x[0] == y[j]) dp[0][j] = 1;
    len[0] = 0;
    repi(j, w) len[j] = max(dp[0][j - 1], len[j - 1]);
    repi(j, h) {
      rep(k, w) if(x[j] == y[k]) dp[j][k] = len[k] + 1;
      repi(k, w) len[k] = max(dp[j][k - 1], max(len[k], len[k - 1]));
      /*rep(k, w) printf("%d ", len[k]);
      printf("\n");*/
    }
    /*printf("\n");
    rep(j, h) {
      rep(k, w) printf("%d ", dp[j][k]);
      printf("\n");
    }*/
    int maxs = 0;
    rep(j, w) if(maxs < dp[h - 1][j]) maxs = dp[h - 1][j];
    printf("%d\n", maxs);
  }
  return 0;
}