dp 暴力 O(N2)

#include<iostream>
#include<string>
#include<ctype.h>

using namespace std;

const int N = 10010;
short dp[N][N];

string a,b;

int main() {
    cin >> a >> b;

    a = ' '+ a;
    b = ' '+ b;

    int la = a.length(), lb = b.length();
    short cnt = 0;
    for(int i = 1; i <= la; i++) {
        for(int j = 1; j <= lb; j++) {
            if (a[i] == b[j] && isalpha(a[i]) && isalpha(b[j])) {
                dp[i][j] = max(dp[i][j], short(dp[i-1][j-1] + 1));
            }
            cnt = max(cnt, dp[i][j]);
        }
    }
    cout<<cnt;
    return 0;
}