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 <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <ctime>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>

#define REP(i,n)   for (int i = 0; i < (n); ++i)
#define SORT(a)    sort((a).begin(), (a).end());
#define UNIQ(a)    SORT(a);(a).erase(unique((a).begin(), (a).end()), (a).end());
#define FIND(a,x)  find((a).begin(), (a).end(), (x)) != (a).end()
#define REVERSE(a) reverse((a).begin(), (a).end());

using namespace std;
using ll = long long;
using P = pair<int,int>;

const int MOD = 1000000007; // 10^9 + 7

int lcs(string x, string y) {
  int m = x.size(), n = y.size();
  int dp[m + 1][n + 1]; memset(dp, 0, sizeof(dp));

  REP(i, m)REP(j, n)
    if (x[i] == y[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]);

  return dp[m][n];
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  srand((unsigned)time(NULL));

  int t; cin >> t;
  REP(i, t) {
    string x, y; cin >> x >> y;

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

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

int main(){
  int q;
  cin>>q;
  while(q--){
    string x,y;
    cin>>x>>y;
    vector<vector<int>> dp(x.size()+1,vector<int>(y.size()+1,0));
    
    for(int xi=0;xi<x.size();++xi){
      for(int yi=0;yi<y.size();++yi){
        if(x[xi]==y[yi]){
          dp[xi+1][yi+1]=dp[xi][yi]+1;
        }else{
          if (dp[xi+1][yi]>dp[xi][yi+1]){
            dp[xi+1][yi+1]=dp[xi+1][yi];
          }else{
            dp[xi+1][yi+1]=dp[xi][yi+1];
          }
        }
      }
    }
    int ans=dp[x.size()][y.size()];
    cout << ans << endl;
  }
}

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

// Dynamic Programming - LCS

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int q;
    cin >> q;

    for (int _ = 0; _ < q; ++_) {
        string s1, s2;
        cin >> s1 >> s2;

        const int s1_size = s1.size();
        const int s2_size = s2.size();
        vector<vector<int>> dp(s1_size + 1);
        for (int i = 0; i < s1_size + 1; ++i) dp[i].resize(s2_size + 1, 0);

        for (int i = 0; i < s1_size; ++i) {
            for (int j = 0; j < s2_size; ++j) {
                if (s1[i] == s2[j]) dp[i+1][j+1] = dp[i][j] + 1;
                else dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
            }
        }
        cout << dp[s1_size][s2_size] << "\n";
    }

    cout << flush;
    return 0;
}

C++: #include<stdio.h>
#include<string.h>
#define MAX 1001
??
int LCSLength(char [], char []);
??
int main()
{
????int i, q, Z[MAX];
????char X[MAX], Y[MAX];
??
????scanf("%d", &q);
????for(i=0; i<q; i++)
????????{
????????????scanf("%s", X);
????????????scanf("%s", Y);
????????????Z[i] = LCSLength(X, Y);
????????}
??
????for(i=0; i<q; i++)
????????{
????????????printf("%d\n", Z[i]);
????????}
????
????return 0;
}
??
int LCSLength(char X[], char Y[])
{
????int i, j, c[MAX][MAX];
????int m = strlen(X);
????int n = strlen(Y);
??
????for(i=1; i<=m; i++) c[i][0] = 0;
????for(j=0; j<=n; j++) c[0][j] = 0;
??
????for(i=1; i<=m; i++)
????????{
????????????for(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-1] >= c[i][j-1]) c[i][j] = c[i-1][j];
????????????else c[i][j] = c[i][j-1];
????????}
????????}
??????
????return c[m][n];
}

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

using namespace std;

string  X,Y;
int q;

int do_dp(int ax,int ay){
  int dp[ax + 100][ay + 100] = {0};
  
  for(int i = 0;i < ax;i++){
    if(X[i] == Y[0]) dp[i][0] = 1;
    if(i > 0) dp[i][0] = max(dp[i][0],dp[i - 1][0]);
  }
  
  for(int j = 0;j < ay;j++){
    if(X[0] == Y[j]) dp[0][j] = 1;
    if(j > 0) dp[0][j] = max(dp[0][j],dp[0][j - 1]);
  }

  for(int i = 1;i < ax;i++){
    for(int j = 1;j < ay;j++){
      if(X[i] == Y[j]){
	dp[i][j] = dp[i - 1][j - 1] + 1;
      }else{
	dp[i][j] = max(dp[i - 1][j],dp[i][j - 1]);
      }
    }
  }
  
  for(int i = 0;i < ax;i++){
    for(int j = 0;j < ay;j++){
      cout << dp[i][j] << " ";
    }
    cout << '\n';
  }
  
  return dp[ax - 1][ay - 1];
}

int main(){
  string str;
  
  cin >> q;
  
  int A[q];
  
  for(int i = 0;i < q;i++){
    cin >> X;
    cin >> Y;
    //cout << X.size() << " " << Y.size() << '\n';
    A[i] = do_dp(X.size(),Y.size());
  }
  
  for(int i = 0;i < q;i++){
    cout << A[i] << '\n';
  }
  
  return 0;
}

C++: #include <iostream>
#include <string>
#define int long long
//#define _DEBUG
using namespace std;
string sa, sb;
int T[1009][1009];
int solve(){
    int sal = sa.length(), sbl = sb.length();
    for(int a=0; a<=sal; a++){
        for(int b=0; b<=sbl; b++){
            if(a==0 || b==0){
                T[a][b] = 0;
            }else if(sa[a-1] == sb[b-1]){
                T[a][b] = 1 + T[a-1][b-1];
            }else{
                T[a][b] = max(T[a][b-1], T[a-1][b]);
            }
        }
    }
    return T[sal][sbl];
}
signed main(){
    int N;
    cin >> N;
    for(int i=0; i<N; i++){
        cin >> sa >> sb;
        cout << solve() << endl;
    }
}