Go: package main

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

//Util
func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func maxInt(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func minInt(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

func absInt(a int) int {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func absFloat64(a float64) float64 {
	if a >= 0 {
		return a
	} else {
		return -a
	}
}

func minFloat64(a, b float64) float64 {
	if a > b {
		return b
	} else {
		return a
	}
}

func str2Int(s string) int {
	n, _ := strconv.Atoi(s)
	return n
}

//Main
var sc = bufio.NewScanner(os.Stdin)
var q int
var X, Y string

func lcs(X, Y string) int {
	lenX := len(X)
	lenY := len(Y)
	dp := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		dp[i] = make([]int, lenY+1)
	}

	res := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if X[i-1] == Y[j-1] {
				dp[i][j] = dp[i-1][j-1] + 1
			} else {
				dp[i][j] = maxInt(dp[i-1][j], dp[i][j-1])
			}
			//fmt.Println(dp)
			res = maxInt(res, dp[i][j])
		}

	}
	return res
}

func main() {
	sc.Split(bufio.ScanWords)
	q = nextInt()

	for i := 0; i < q; i++ {
		X = nextStr()
		Y = nextStr()

		fmt.Println(lcs(X, Y))
	}
}

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

int lcs(string &X, string &Y) {
  int dp[1000 + 1][1000 + 1];
  int max = 0;
  int m = X.size();
  int n = Y.size();
  X = ' ' + X;
  Y = ' ' + Y;

  for (int i = 1; i <= m; i++)
    dp[i][0] = 0;

  for (int i = 1; i <= n; i++)
    dp[0][i] = 0;

  for (int i = 1; i <= m; i++) {
    for (int j = 1; j <= n; j++) {
      if (X[i] == Y[j])
	dp[i][j] = dp[i-1][j - 1] + 1;
      else if (dp[i - 1][j] >= dp[i][j - 1])
	dp[i][j] = dp[i - 1][j];
      else
	dp[i][j] = dp[i][j - 1];

      if(max < dp[i][j])
	max = dp[i][j];
    }
  }

  return max;
}

int main() {
  int N = 0;
  cin >> N;

  string X, Y;
  for (int i = 0; i < N; i++) {
    cin >> X >> Y;

    cout << lcs(X, Y) << endl;
  }

  return 0;
}

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

int c[1010][1010];

void lcs(char X[], char Y[]){
	int m = strlen(X);
	int n = strlen(Y);
	int i, j;
	for(i = 1;i <= m;i++)
		c[i][0] = 0;
	for(j = 1;j <= m;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]);
		}
	}
}

int main(void){
	int q, i;
	char A[1000], B[1000];
	scanf("%d", &q);
	for(i = 0;i < q;i++){
		scanf("%s", A);
		scanf("%s", B);
		lcs(A, B);
		printf("%d\n", c[strlen(A)][strlen(B)]);
	}
	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;
    
    
  }
}

C++: #include <algorithm>
#include <bitset>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using namespace std;

int solve() {
    string x, y;
    cin >> x >> y;
    vector<vector<int>> dp(x.size() + 1, vector<int>(y.size() + 1, 0));

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

    return dp[x.size()][y.size()];
}

int main() {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cout << solve() << endl;
    }
}

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

int c[1010][1010];

void lcs(char X[], char Y[]){
	int m = strlen(X);
	int n = strlen(Y);
	int i, j;
	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 - 1] == Y[j - 1])
				c[i][j] = c[i - 1][j - 1] + 1;
			else
				c[i][j] = max(c[i - 1][j], c[i][j - 1]);
		}
	}
}

int main(void){
	int q, i;
	char A[1000], B[1000];
	scanf("%d", &q);
	for(i = 0;i < q;i++){
		scanf("%s", A);
		scanf("%s", B);
		lcs(A, B);
		printf("%d\n", c[strlen(A)][strlen(B)]);
	}
	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];

void solve()
{
  REP(i, str1.size())
    if(str1[i] == str2[str2.size() - 1])
      dp[i][str2.size() - 1] = 1;
    else
      dp[i][str2.size() - 1] = 0;
  for(int i = str2.size() - 2; i >= 0; i--)
    if(str1[str1.size() - 1] == str2[i])
      dp[str1.size() - 1][i] = 1;
    else
      dp[str1.size() - 1][i] = dp[str1.size() - 1][i + 1];
  for(int i = str1.size() - 2; i >= 0; i--){
    for(int j = str2.size() - 2; j >= 0; j--){
      if(str1[i] == str2[j])
	dp[i][j] = dp[i + 1][j + 1] + 1;
      else
	dp[i][j] = max(dp[i + 1][j], dp[i][j + 1]);
    }
  }
}
  
int main()
{
  int q;
  cin >> q;
  cin.ignore();
  REP(i, q){
    getline(cin, str1);
    getline(cin, str2);
    fill(&dp[0][0], &dp[1001][0], -1);
    swap(str1, str2);
    solve();
    cout << dp[0][0] << endl;
  }
}

C++: #include <stack>
#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
using namespace std;
int gcd(int a, int b)
{
   if (a%b == 0)
   {
       return(b);
   }
   else
   {
       return(gcd(b, a%b));
   }
}
int mod = 1000000000 + 7;
vector<int> v;
class Calc
{
    // 宣言
    long long a;

    public:
        // 素因数分解
        void decompositPrime(long long a);
};

/*
 * 素因数分解
 */
void Calc::decompositPrime(long long n)
{
    // 割る数の初期値
    a = 2;
    // √n ≧ a ( n ≧ a * a ) の間ループ処理
    while (n >= a * a) {
        // a で割り切れたら、a は素因数
        // そして、割られる数を a で割る
        // a で割り切れなかったら、 a を 1 増加させる
        if (n % a == 0) {
            //printf("%d * ", a);
             v.push_back(a);
            n /= a;
        } else {
            a++;
        }
    }
    // 最後に残った n は素因数
    v.push_back(n);
    //printf("%d\n", n);
}

int main(){
    //std::stack<int> stack;
    int n;
    cin >> n;
    for(int i = 0; i < n; i++){
        string a,b;
        cin >> a >> b;
        int asize = a.size();
        int bsize = b.size();
        int mat[asize+1][bsize+1];
        a = " " + a;
        b = " " + b;
        mat[0][0] = 0;
        for(int i = 1; i <= asize; i++){
            mat[i][0] = 0;
        }
        for(int i = 1; i <= bsize; i++){
            mat[0][i] = 0;
        }
        for(int j = 1; j <= asize; j++){
            for(int k = 1; k <= bsize; k++){
                if(a[j] == b[k]){
                    mat[j][k] = mat[j-1][k-1]+1;
                }else{
                    mat[j][k] = max(mat[j-1][k], mat[j][k-1]);
                }
            }
        }
        // for(int i = 0; i <= asize; i++){
        //     for(int j = 0; j <= bsize; j++){
        //         cout << mat[i][j] << " ";
        //     }
        //     cout << endl;
        // }
        cout << mat[asize][bsize] << endl;
    }
    //cout << ans << endl;
    return 0;
}