lcs2.cpp

#include <algorithm>
#include <iostream>
#include <vector>

using std::vector;

int lcs2(vector<int> &a, vector<int> &b) {
    int n = a.size(), 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 (i == 0 || j == 0)
                dp[i][j] = 0;
            else if (a[i - 1] == b[j - 1])
                dp[i][j] = dp[i - 1][j - 1] + 1;
            else
                dp[i][j] = std::max(dp[i - 1][j], dp[i][j - 1]);
    return dp[n][m];
}

int main() {
    size_t n;
    std::cin >> n;
    vector<int> a(n);
    for (size_t i = 0; i < n; i++) {
        std::cin >> a[i];
    }

    size_t m;
    std::cin >> m;
    vector<int> b(m);
    for (size_t i = 0; i < m; i++) {
        std::cin >> b[i];
    }

    std::cout << lcs2(a, b) << std::endl;
}