Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}
	for i := 0; i < n; i++ {
		strX := nextText(sc)
		strY := nextText(sc)
		fmt.Println(calcLcs(strX, strY))
	}
}

func calcLcs(strX, strY string) int {
	lenX, lenY := len(strX), len(strY)
	memo := make([][]int, lenX+1)
	for i := 0; i < lenX+1; i++ {
		memo[i] = make([]int, lenY+1)
	}

	lcs := 0
	for i := 1; i < lenX+1; i++ {
		for j := 1; j < lenY+1; j++ {
			if strX[i-1] == strY[j-1] {
				memo[i][j] = memo[i-1][j-1] + 1
			} else {
				if memo[i-1][j] > memo[i][j-1] {
					memo[i][j] = memo[i-1][j]
				} else {
					memo[i][j] = memo[i][j-1]
				}
			}
			if memo[i][j] > lcs {
				lcs = memo[i][j]
			}
		}
	}
	return lcs
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include<iostream>
#include<cstring>
#define LcsMaxLen 1005
using namespace std;
char sf[LcsMaxLen];
char ss[LcsMaxLen];
int mark[LcsMaxLen][LcsMaxLen]={0};
int LcsLen( int sfi,int ssi ){
	if(sfi<0||ssi<0)
		return 0;
	if(mark[sfi][ssi])return mark[sfi][ssi];
	if(sf[sfi]==ss[ssi]){
		mark[sfi][ssi] = LcsLen(sfi-1,ssi-1)+1;
		return mark[sfi][ssi];
	}
	else {
		mark[sfi][ssi] = max(LcsLen(sfi,ssi-1),LcsLen(sfi-1,ssi));
		return mark[sfi][ssi];
	}
} 
int main(){
	int n,len;
	cin>>n;
	while(n--){
	cin>>sf>>ss;
	len = max(strlen(sf),strlen(ss));
	for(int i = 0;i<len;++i)
		for(int j = 0;j<len;++j)
			mark[i][j]=0;
	cout<<LcsLen(strlen(sf)-1,strlen(ss)-1)<<endl;
	} 
	return 0;
}

C++: #include <iostream>

using namespace std;

int ans(string a, string b) {
  int n = a.size();
  int m = b.size();
  int memo[n+1][m+1];
  for (int i = 0; i <= n; i++) {
    for (int j = 0; j <= m; j++) {
      memo[i][j] = 0;
    }
  }

  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      int res = max(memo[i-1][j], memo[i][j-1]);
      if (a[i] == b[j]) {
        res = max(res, memo[i-1][j-1] + 1);
      } else {
        res = max(res, memo[i-1][j-1]);
      }
      memo[i][j] = res;
    }
  }
  
  return memo[n][m];
}

int main() {
  int q;
  cin >> q;

  for (int i = 0; i < q; i++) {
    string a, b;
    cin >> a >> b;
    
    cout << ans(a, b) << endl;
  }

  return 0;
}

C++: #include<iostream>
#include<vector>
using namespace std;
int main()
{
	int kurikaeshi;
	vector<int> answer;
	cin >> kurikaeshi;
	for (int variable = 0;variable < kurikaeshi;++variable) {
		char X[1024], Y[1024];
		int LX = 0, LY = 0;
		vector<vector<int>> L;
		cin >> X >> Y;
		for (int i = 0;X[i] != 0;++i) LX += 1;
		for (int j = 0;Y[j] != 0;++j) LY += 1;
		L.resize(LX+1);
		for (int k = 0;k < LX + 1;++k) L[k].resize(LY+1);
		for (int i = 0;i<LX+1;++i) {
			for (int j = 0;j<LY+1;++j) {
				if (i == 0 || j == 0) {
					L[i][j] = 0;
				}
				else if (X[i-1] == Y[j-1]) {
					L[i][j] = L[i][j-1] + 1;
				}
				else {
					L[i][j] = L[i-1][j] > L[i][j-1] ? L[i-1][j] : L[i][j-1];
				}
			}
		}
		answer.push_back(L[LX][LY]);
	}
	for (int variable = 0;variable < kurikaeshi;++variable) {
		cout << answer[variable] << endl;
	}
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<numeric>
#include<string>
#include<cmath>
#include<set>
#include<queue>
#include<bitset>
#include<iomanip>
#include<cctype>
using namespace std;
const int inf = 1001001000;

void print(vector<vector<int>> a){
	for (int i=0;i<a.size();i++){
		for (int j=0;j<a[i].size();j++){
			cout << a[i][j] << " ";
		}
		cout << endl;
	}
}

void print(vector<int> a){
    int n = a.size();
    for (int j=0;j<n;j++) {
        if (j != n-1) cout << a[j] << " ";
        else cout << a[j] << endl;
    }
}

int main(){
    int q; cin >> q;
    for (int i = 0; i < q; i++){
        string a, b; cin >> a >> b;
        vector<vector<int>> dp(a.size()+1,vector<int>(b.size()+1,0));
        for (int k = 1; k < a.size()+1; k++){
            for (int l = 1; l < b.size()+1; l++){
                if (a[k-1] == b[l-1]){
                    dp[k][l] = max({dp[k-1][l-1]+1,dp[k-1][l],dp[k][l-1]});
                }
                else dp[k][l] = max(dp[k-1][l],dp[k][l-1]);
            }
        }
        cout << dp[a.size()][b.size()] << endl;
    }

    return 0;
}

C++: /*
 * ALDS1_10_C.cpp
 *
 *  Created on: May 5, 2018
 *      Author: 13743
 */

#include<cstdio>
#include<cstring>
#include<algorithm>

int dp[1001][1001];
bool dpR[1001][1001];

int lcm(char* X, char* Y, int nx, int ny) {
	dp[1][1] = (X[0] == Y[0]);
	for(int i=1; i<=nx; i++) {
		for(int j=1; j<=ny; j++) {
			dp[i][j] = (X[i-1]==Y[j-1]) + dp[i-1][j-1];
			dp[i][j] = std::max(dp[i-1][j], dp[i][j]);
			dp[i][j] = std::max(dp[i][j-1], dp[i][j]);
		}
	}
	return dp[nx][ny];
}

int lcmRec(char* X, char* Y, int nx, int ny) {
	if(nx <=0 || ny <= 0) return 0;
	if(!dpR[nx][ny]) {
		dpR[nx][ny] = 1;
		dp[nx][ny] = lcmRec(X, Y, nx-1, ny-1) + (X[nx-1]==Y[ny-1]);
		dp[nx][ny] = std::max(lcmRec(X, Y, nx-1, ny), dp[nx][ny]);
		dp[nx][ny] = std::max(lcmRec(X, Y, nx, ny-1), dp[nx][ny]);
	}
	return dp[nx][ny];
}

int main() {
	int q;
	scanf("%d", &q);
	char X[1001];
	char Y[1001];
	while(q--) {
		for(int i=0; i<1001; i++) {
			for(int j=0; j<1001; j++) {
				dpR[i][j] = dp[i][j] = 0;
			}
		}
		scanf("%s", X);
		scanf("%s", Y);
		int nx = (int)strlen(X);
		int ny = (int)strlen(Y);
		//printf("%d\n", lcm(X, Y, nx, ny));
		printf("%d\n", lcmRec(X, Y, nx, ny));
	}
}

C++: #include <iostream>
#include <vector>
#include <cmath>
#include <algorithm>
#include <string>
#include <sstream>
#include <utility>
#define ll long long int
#define rep(i,x,y) for(int i=x;i<y;i++)
#define rel(i,x,y) for(int i=x-1;i>=y;i--)
#define all(x) x.begin(),x.end()
#define mod 1000000007
using namespace std;

int main(){
	int q;
	cin >> q;
	string X[q],Y[q];
	rep(i,0,q){
		cin >> X[i];
		cin >> Y[i];
	}

	rep(i,0,q){
		int m = X[i].length();
		int n = Y[i].length();
		int dp[m+1][n+1] = {};
		int maxl=0;
		rep(j,0,m){
			rep(k,0,n){
				if(X[i][j] == Y[i][k]) dp[j+1][k+1] = dp[j][k]+1;
				else dp[j+1][k+1] = max(dp[j][k+1],dp[j+1][k]);
			}
		}
		cout << dp[m][n] << endl;
	}
	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 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;
	string s1, s2;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> s1 >> s2;
		cout << lcs(s1, s2) << endl;
	}
    return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
using namespace std;
static const int N = 1001;

int lcs(string X, string Y){
    int c[N][N];
    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 j = 0; 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 = max(maxl, c[i][j]);
        }
    }
    return maxl;
}
int main(){
    int q;
    cin >> q;
    while(q--){
        string a,b; cin >> a >> b;
        cout << lcs(a,b) << endl;
    }
}