487.cpp

#include <bits/stdc++.h>
using namespace std;
char a[30][30];
int N, M;
vector<string> vv;
string s;
vector<char> v;
int xx[] = {-1, -1, -1, 0, 0, 1, 1, 1};
int yy[] = {-1, 0, 1, -1, 1, -1, 0, 1};
void call(int i, int j) {
    if (i < 0 || j < 0 || i >= N || j >= N) return;
    if (v.size() >= 3) {
        s.clear();
        for (int k = 0; k < v.size(); k++) {
            s += v[k];
        }
        vv.push_back(s);
    }
    for (int k = 0; k < 8; k++) {
        int r = i + xx[k];
        int c = j + yy[k];
        if (r >= 0 && c >= 0 && r < N && c < N && a[r][c] > a[i][j]) {
            v.push_back(a[r][c]);
            call(r, c);
            v.pop_back();
        }
    }
    return;
}

bool comp(string s, string x) {
    if (s.size() == x.size())
        return s < x;
    else
        return s.size() < x.size();
}

int main() {
    int tc, n;
    int t = 0;
    scanf("%d", &tc);
    for (t = 0; t < tc; t++) {
        scanf("%d", &N);
        int i, j, k;
        getchar();
        for (i = 0; i < N; i++) gets(a[i]);
        vv.clear();
        for (i = 0; i < N; i++) {
            for (j = 0; j < N; j++) {
                v.clear();
                v.push_back(a[i][j]);
                call(i, j);
            }
        }
        sort(vv.begin(), vv.end(), comp);
        if (t != 0) puts("");
        for (i = 0; i < vv.size(); i++) {
            if (i == 0 || vv[i] != vv[i - 1]) printf("%s\n", vv[i].c_str());
        }
    }
    return 0;
}