Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	Q := sc.nextInt()
	for q := 0; q < Q; q++ {
		X, Y := sc.nextStr(), sc.nextStr()
		xLen, yLen := len(X), len(Y)
		dp := make([][]int, xLen+1)
		for i := 0; i <= xLen; i++ {
			dp[i] = make([]int, yLen+1)
		}
		for x := 0; x <= xLen; x++ {
			for y := 0; y <= yLen; y++ {
				if x == 0 || y == 0 {
					dp[x][y] = 0
				} else if X[x-1] == Y[y-1] {
					dp[x][y] = dp[x-1][y-1] + 1
				} else {
					dp[x][y] = max(dp[x-1][y], dp[x][y-1])
				}
			}
		}
		fmt.Fprintln(wtr, dp[xLen][yLen])
	}

	wtr.Flush()
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
static const int N=1000;

int lcs(string X,string Y){
  int c[N+1][N+1];
  int m=X.size();
  int n=Y.size();
  int i,j;
  int maxl=0;
  X= ' ' + X;
  Y= ' ' + Y;
 
  for(i=1;i<=m;i++) c[i][0]=0;
  for(j=1;j<=n;j++) c[0][j]=0;

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

C++: #include<stdio.h>

int hantei(char x[], char y[]) {
  int xn = 0, yn = 0, flag = 0, i, j, max = 0;
  int c[101][101];
  
  while (flag == 0)
  {
    if (x[xn] == '\0')
    {
      xn++;
    }
    else
    {
      flag = 1;
    }
  }
  
  flag = 0;
  
  while (flag == 0)
  {
    if (y[yn] == '\0')
    {
      yn++;
    }
    else
    {
      flag = 1;
    }
  }
  for (i = 1; i < xn + 1; i++) c[i][0] = 0;
  for (j = 1; j < yn + 1; j++) c[0][j] = 0;
  
  for (i = 1; i < xn + 1; i++)
  {
    for (j = 1; j < yn + 1; 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];
      }
      if (max < c[i][j]) max = c[i][j];
    }
  }
  
  return max;
}

int main(void) {
  char x[1000], y[1000];
  int q, i;
  
  scanf("%d", &q);
  
  for (i = 0; i < q; i++)
  {
    scanf("%s", x);
    scanf("%s", y);
    printf("%d\n", hantei(x, y));
  }
  
  return 0;
}

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

using namespace std;

#define FOR(i,s,e) for((i)=(s);(i)<(int)(e);(i)++)
#define REP(i,e) FOR(i,0,e)

#define all(o) (o).begin(), (o).end()
#define psb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))

typedef long long ll;
typedef pair<int, int> PII;

const double EPS = 1e-10;

const int N = 1000;
char s[N+1], t[N+1];
int ls, lt;
int q;
int dp[N+1][N+1];
//dp[i][j] = s[0]...s[i+1]??¨t[0]...t[j+1]???LCS
//(1<=i<=ls, 1<=j<=lt)

int main() {
  int i, j, k;
  scanf("%d ", &q);
  for (k=0; k<q; k++) {
    ls = lt = 0;
    memset(s, 0, sizeof(s)), scanf("%s ", s);
    memset(t, 0, sizeof(t)), scanf("%s ", t);
    while (s[ls]) ls++;
    while (t[lt]) lt++;

    memset(dp, 0, sizeof(dp));
    for (i=1; i<=ls; i++)
      for (j=1; j<=lt; j++) {
        if (s[i]==t[j])
          dp[i][j] = dp[i-1][j-1] + 1;
        else
          dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
      }

    printf("%d\n", dp[ls][lt]);
  }

  return 0;
}

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

static const int N = 1000;

int lcs(string X,string Y){
    int C[N+1][N+1];
    int m = X.size();
    int n = Y.size();
    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{
             C[i][j] = max(C[i-1][j],C[i][j-1]);
         }
            maxl = C[i][j];
        }
    }
    return maxl;
}


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

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

int LCS(std::string str1, std::string str2, int i, int j){
  if(str1[i] == str2[j]){
    return 1;
  }
  else{
    return 0;
  }
}

int max(int a, int b, int c){
  int m = a;
  if(b > m){
    m = b;
  }
  if(c > m){
    m = c;
  }
  return m;
}

int main(){
  int q;
  std::cin >> q;
  int ans[q];
  std::string str1, str2;
  for(int z=0; z<q; z++){
    std::cin >> str1 >> str2;
    int l1 = str1.size();
    int l2 = str2.size();
    int DP[l1+1][l2+1] = {};

    for(int i=1; i<=l1; i++){
      for(int j=1; j<=l2; j++){
	DP[i][j] = max(DP[i-1][j], DP[i][j-1], DP[i-1][j-1] + LCS(str1, str2, i-1, j-1));
      }
    }
    ans[z] = DP[l1][l2];
  }

  for(int z=0; z<q; z++){
    std::cout << ans[z] << std::endl;
  }
  return 0;
}

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

int Max(int &a,int b){return a=max(a,b);}

int LCS(string &a,string &b){
  int n = a.size();
  int m = b.size();
  vector <vector<int> > dp(n+1,vector<int>(m+1));

  for(int i=0;i<n;i++)
    for(int j=0;j<m;j++){
      if(a[i] == b[j]) Max(dp[i+1][j+1],dp[i][j]+1);
      Max(dp[i+1][j],dp[i][j]);
      Max(dp[i][j+1],dp[i][j]);
    }
  return dp[n][m];
}

int main(){
  int q;
  cin>>q;
  while(q--){
    string a,b;
    cin>>a>>b;
    cout<<LCS(a,b)<<endl;
  }
  return 0;
}

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

int main(){
  int q;
  cin >> q;
  for(int m=0; m<q; m++){
    string wordx, wordy;
    cin >> wordx >> wordy;
    int L[1000][1000]={0};
    
    for(int j=0; j<wordy.size(); j++){
      for(int i=0; i<wordx.size(); i++){
	if(wordx[i]==wordy[j]){
	  L[i][j] = 1+L[i-1][j-1];
	}
	else{
	  L[i][j] = max(L[i][j-1], L[i-1][j]);
	}
      }
    }
    cout << L[wordx.size()-1][wordy.size()-1] << endl;
    
    
  }
}