Go: package main

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

func max(x, y int) int {
	if x < y {
		return y
	} else {
		return x
	}
}

/*********************************************************************
長さmの列X_(m)と長さnの列Y_(n)の最長共通部分列LCSは、
	(1)X[m] == Y[n]ならば、X_(m-1)とY_(n-1)のLCSにX[m]を繋げたもの
	(2)X[m] != Y[n]ならば、X_(m-1)とY_(n)のLCSもしくはX_(m)とY_(n-1)のLCS
	のいずれかのうち長い方

c[m+1][n+1]：c[i][j]にX_(i)とY_(j)のLCSの長さを格納する二次元配列
*********************************************************************/

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Scan()
	n, _ := strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		scanner.Scan()
		s1 := scanner.Text()
		scanner.Scan()
		s2 := scanner.Text()
		s1, s2 = " " + s1 , " " + s2
		c := make([][]int, len(s1))
		for i := range c {
			c[i] = make([]int, len(s2))
		}

		LCS := 0

		for i := 1; i < len(s1); i++ {
			for j := 1; j < len(s2); 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])
				}
				LCS = max(LCS, c[i][j])
			}
		}
		fmt.Println(LCS)
	}
}

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

int main() {

  int q;
  cin >> q;
  
  while (0 < q) {
    
    string X, Y;
    cin >> X >> Y;

    int x = X.size();
    int y = Y.size();

    // X_0 ... X_i と Y_0 ... Y_j に対するLCSの長さ
    vector<vector<int>> dp(x+1, vector<int>(y+1));

    int answer = 0;

    for (int i = 0; i < x; i++) {
      for (int j = 0; j < y; j++) {
        if (X[i] == Y[j]) {
          // 同じ文字列の場合は、
          // X_0 ... X_i と Y_0 ... Y_j に対するLCSに1加える
          dp[i+1][j+1] = dp[i][j] + 1;
        } else {
          // 違う場合は、
          // X_0 ... X_i と Y_0 ... Y_j+1 に対するLCSと
          // X_0 ... X_i+1 と Y_0 ... Y_j に対するLCSで
          // 大きい方
          dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
        }
        answer = max(answer, dp[i+1][j+1]);
      }
    }

    cout << answer << endl;

    q--;
  }

  return 0;

}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<string>
#include<cmath>
#include<cstdio>
#include<queue>
#include<deque>
#include<map>
#include<stack>
#include<set>
#include<utility>
using namespace std;
typedef pair<int,int> ii;
typedef long long ll;
typedef pair<ll,ii> P;
typedef unsigned long long int ull;
const int MOD=1e9+7;
int dy[]={1,0,-1,0};
int dx[]={0,1,0,-1};
const int MAXN=100000;
const int MAXE=100000;
const int MAXV=10000;
const ll INF=2e18;

int main(){
    int q;cin>>q;
    int dp[1001][1001];
    for(int k=0;k<q;k++){
        string s,t;cin>>s>>t;
        int n=(int)s.size();
        int m=(int)t.size();
        for(int i=0;i<=n;i++){
            for(int j=0;j<=m;j++){
                dp[i][j]=0;
            }
        }
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                dp[i+1][j+1]=max(dp[i+1][j],dp[i][j+1]);
                if(s[i]==t[j]) dp[i+1][j+1]=max(dp[i+1][j+1],dp[i][j]+1);
            }
        }
        cout<<dp[n][m]<<endl;
    }
    return 0;
}

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

using namespace std;

int dp[1010][1010];



int solve() {

	string s,t;

	cin >> s >> t;


	int max_s = s.length();
	int max_t = t.length();

	memset(dp,0, sizeof(int) * 1010 * 1010);



	for (int i = 1; i <= max_s; i++) {
		for (int j = 1; j <= max_t; j++) {
			if (s.at(i - 1) == t.at(j -1)) {
				dp[i][j] = dp[i - 1][j - 1] + 1;
			} else {
				dp[i][j] = max(dp[i][j - 1],dp[i -1][j]);			
			}
		}
	}
	return dp[max_s][max_t];
}

int main() {
	int q;

	cin >> q;

	for (int i = 0; i  < q; i++) {
		cout << solve() << endl;
	}

}

C++: #include <bits/stdc++.h>
#define INF 100000

using namespace std;
typedef long long int ll;

int dh[4] = {1,0,-1,0};
int dw[4] = {0,1,0,-1};

int main()
{
    int q;
    cin >> q;
    for(int i = 0; i < q; i++)
    {
        string X,Y;
        cin >> X >> Y;
        int lx = X.length();
        int ly = Y.length();
        vector<vector<int>>dp(lx+1,vector<int>(ly+1,0));
        for(int i = 1; i <= lx; i++)
        {
            for(int j = 1; j <= ly; j++)
            {
                if(X[i-1] == Y[j-1]) dp[i][j] = dp[i-1][j-1] + 1;
                else dp[i][j] = max(dp[i-1][j],dp[i][j-1]);
            }
        }
        cout << dp[lx][ly] << endl;
    }
}

C++: #include <iostream>
#include <cstdio>
#include <cctype>
#include <cstring>
#include <cmath>
#include <cstdarg>
#include <cstdlib>
#include <string>

#include <vector>
#include <tuple>
#include <stack>
#include <queue>
#include <algorithm>
using namespace std;

int nxtx[] = {1, 0};
int nxty[] = {0, 1};

int main(int argc, char const *argv[]) {
    int q;
    cin >> q;
    string X, Y;
    typedef pair<int, int> pint;
    for (int k = 0; k < q; k ++) {
        cin >> X;
        cin >> Y;
        int lenX = X.size();
        int lenY = Y.size();
        int dp[lenX + 1][lenY + 1];
        for (int i = 0; i <= lenX; i ++) {
            dp[i][0] = 0;
        }
        for (int i = 0; i <= lenY; i ++) {
            dp[0][i] = 0;
        }

        for (int i = 1; i <= lenX; i ++) {
            for (int j = 1; j <= lenY; j ++) {
                if (X[i-1] == Y[j-1]) {
                    dp[i][j] = dp[i-1][j-1] + 1;
                } else {
                    dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
                }
            }
        }
        cout << dp[lenX][lenY] << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <queue>
#include <vector>
#include <algorithm>
#include <map>

int main(){
  int q;
  scanf("%d",&q);
  std::vector<std::string > X(q);
  std::vector<std::string > Y(q);
  for (int i=0; i<q; i++){
    std::cin >> X[i];
    std::cin >> Y[i];
  }
  int val[1002][1002];
  for (int k=0; k<q; k++){
    for (int i=0; i<X[k].length(); i++){
      for (int j=0; j<Y[k].length(); j++){
        if (X[k][i]==Y[k][j]){
          if (i==0 && j==0){
            val[i][j]=1;
          }
          if (i>0 && j>0){
            val[i][j]=val[i-1][j-1]+1;
          } else {
            val[i][j]=1;
          }
        } else if (i==0 && j==0){
          val[i][j]=0;
        } else if (i==0){
          val[i][j]=val[i][j-1];
        } else if (j==0){
          val[i][j]=val[i-1][j];
        } else {
          val[i][j]=std::max(val[i-1][j], val[i][j-1]);
        }
      }
    }
    int length = val[X[k].length()-1][Y[k].length()-1];
    printf("%d\n", length);
  }
  return 0;
}

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

using namespace std;

int solve(string s1, string s2){
    int L[s1.size()+1][s2.size()+1];
    for(int i=0;i<s1.size();i++){
        for(int j=0;j<s2.size();j++){
            if(i==0 || j==0){
                L[i][j]=0;
            }
            else if(s1[i] == s2[j]){
                L[i][j] = 1 + L[i-1][j-1];
            }
            else{
                L[i][j] = max(L[i][j-1],L[i-1][j]);
            }
        }
    }
    return L[s1.size()][s2.size()];
}

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

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

#define MAX 1000
int dp[MAX+1][MAX+1];

int lcs(string X, string Y){
    int m = X.size();
    int n = Y.size();
    for(int i = 0; i <= m; i++) dp[i][0] = 0;
    for(int j = 0; j <= n; j++) dp[0][j] = 0;

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

    return dp[m][n];
}

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

    string X, Y;

    for(int i = 0; i < q; i++){
        cin >> X >> Y;
        cout << lcs(X,Y) << endl;
    }

    return 0;

}