Hiding Places Solution:

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

int main(){
    // #ifndef TESTING
    // freopen("input.txt", "r", stdin);
    // freopen("output.txt", "w", stdout);
    // #endif

    int cases;
    cin >> cases;
    while(cases--){
        queue<pair<int, int>> q;
        set<pair<int, int>> queued;
        pair<bool, bool> board[8][8] = {};
        char col, row;
        cin >> col >> row;
        col -= 'a';
        row -= '1';
        q.push({col, row});
        int pieces = q.size();
        int placed = 0, iterations = 0;
        while(placed + q.size() < 64){
            pieces = q.size();
            iterations++;
            for(int i = 0; i < pieces; i++){
                placed++;
                pair<int, int> coord = q.front();
                int x = coord.first, y = coord.second;
                q.pop();
                board[x][y].first = true;
                board[x][y].second = true;
                if(x - 2 >= 0 && y - 1 >= 0 && !board[x - 2][y - 1].first && !board[x - 2][y - 1].second){
                    board[x - 2][y - 1].second = true;
                    q.push({x - 2, y - 1});
                }
                if(x - 2 >= 0 && y + 1 < 8 && !board[x - 2][y + 1].first && !board[x - 2][y + 1].second){
                    board[x - 2][y + 1].second = true;
                    q.push({x - 2, y + 1});
                }
                if(x + 2 < 8 && y - 1 >= 0 && !board[x + 2][y - 1].first && !board[x + 2][y - 1].second){
                    board[x + 2][y - 1].second = true;
                    q.push({x + 2, y - 1});
                }
                if(x + 2 < 8 && y + 1 < 8 && !board[x + 2][y + 1].first && !board[x + 2][y + 1].second){
                    board[x + 2][y + 1].second = true;
                    q.push({x + 2, y + 1});
                }
                if(x - 1 >= 0 && y - 2 >= 0 && !board[x - 1][y - 2].first && !board[x - 1][y - 2].second){
                    board[x - 1][y - 2].second = true;
                    q.push({x - 1, y - 2});
                }
                if(x - 1 >= 0 && y + 2 < 8 && !board[x - 1][y + 2].first && !board[x - 1][y + 2].second){
                    board[x - 1][y + 2].second = true;
                    q.push({x - 1, y + 2});
                }
                if(x + 1 < 8 && y - 2 >= 0 && !board[x + 1][y - 2].first && !board[x + 1][y - 2].second){
                    board[x + 1][y - 2].second = true;
                    q.push({x + 1, y - 2});
                }
                if(x + 1 < 8 && y + 2 < 8 && !board[x + 1][y + 2].first && !board[x + 1][y + 2].second){
                    board[x + 1][y + 2].second = true;
                    q.push({x + 1, y + 2});
                }
            }
        }
        cout << iterations << " ";
        vector<pair<int, int>> v;
        while(q.size()){
            v.push_back(q.front());
            q.pop();
        }
        sort(v.begin(), v.end(), [](const pair<int, int> &a, const pair<int, int> &b){
            return a.second > b.second ? true : a.second < b.second ? false : a.first < b.first;
        });
        for(auto i : v){
            cout << (char) (i.first + 'a') << (char) (i.second + '1') << " ";
        }
        cout << endl;

    }
       
    return 0;   
}