Hiitism

input/code.cpp: In function 'std::ostream& operator<<(std::ostream&, std::vector<std::vector<_Tp> >)':
input/code.cpp:10:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   10 |     for(const auto& x : v) os << x << " "; cout << "\n";} return os;
      |     ^~~
input/code.cpp:10:44: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   10 |     for(const auto& x : v) os << x << " "; cout << "\n";} return os;
      |                                            ^~~~

#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
#define all(x) x.begin(), x.end()
#define rep(i,a,b) for(int i=a; i<=b; i++)
template<typename T> ostream& operator<<(ostream& os, const vector<T> v){ for(const auto& x : v) os << x << " "; return os; }
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>> y){
    for(const auto& v : y){
    for(const auto& x : v) os << x << " "; cout << "\n";} return os;
}
 
int findrow(vector<vector<char>>& s, ll n, ll m){
    for(int i=0; i<n; i++){
        char c = s[i][0];
        if(c == '.')
            continue;
        bool x = true;
        for(int j=1; j<m; j++){
            if(s[i][j] != c){
                x = false;
                break;
            }
        }
        if(x){
            return i;
        }
    }
    return -1;
}
 
int findcol(vector<vector<char>>& s, ll n, ll m){
    for(int i=0; i<m; i++){
        char c = s[0][i];
        if(c == '.')
            continue;
        bool x = true;
        for(int j=1; j<n; j++){
            if(s[j][i] != c){
                x = false;
                break;
            }
        }
        if(x){
            // cout << "here: " << i << "\n" << s << "\n\n";
            return i;
        }
    }
    return -1;
}
 
int main(){
    ios::sync_with_stdio(0);
 
    vector<vector<char>> s;
 
    ll n0,m0;
    cin >> n0 >> m0;
    ll n = n0, m = m0;
 
    for(int i=0; i<n0; i++){
        string s2;
        cin >> s2;
        vector<char> row;
        for(int j=0; j<m0; j++){
            row.push_back(s2[j]);
        }
        s.push_back(row);
        // cout << row << "\n";
    }
 
    vector<int> ridxs;
    vector<int> cidxs;
 
    for(int i=0; i<n0; i++){
        ridxs.push_back(i+1);
    }
    for(int i=0; i<m0; i++){
        cidxs.push_back(i+1);
    }
 
    vector<string> res;
 
    while(n>1 && m>1){
        // cout << "\n\nthis:\n" << s << "\n\n";
 
        int c = findrow(s, n, m);
        if(c != -1){
            string r;
            r += "R "; r += to_string(ridxs[c]); r += " "; r += s[c][0];;
            res.push_back(r);
            // res << "R " << ridxs[c] << " " << s[c][0] << "\n";
            s.erase(s.begin()+c);
            n --;
            ridxs.erase(ridxs.begin()+c);
            continue;
        }
 
        c = findcol(s, n, m);
        if(c != -1){
            string r;
            r += "C "; r += to_string(cidxs[c]); r += " "; r += s[0][c];
            res.push_back(r);
            // res << "C " << cidxs[c] << " " << s[0][c] << "\n";
            for(int i=0; i<m; i++){
                s[i].erase(s[i].begin() + c);
            }
            m --;
            cidxs.erase(cidxs.begin()+c);
            continue;
        }
        break;
    }
    for(const auto& v : s){
        for(const auto& x : v){
            if(x != '.'){
                cout << "Impossible\n";
                return 0;
            }
        }
    }
    
    // TODO: REverse output
    res = vector(res.rbegin(), res.rend());
    for(const auto& r : res)
        cout << r << "\n";
 
    // if here, impossible
}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: RUNTIME ERROR

Test 4

Verdict: RUNTIME ERROR

Test 5

Verdict: RUNTIME ERROR

Test 6

Verdict: ACCEPTED

Test 7

Verdict: RUNTIME ERROR

Test 8

Verdict: RUNTIME ERROR

Test 9

Verdict: RUNTIME ERROR

Test 10

Verdict: RUNTIME ERROR

Test 11

Verdict: RUNTIME ERROR

Test 12

Verdict: RUNTIME ERROR

Test 13

Verdict: RUNTIME ERROR

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: RUNTIME ERROR

Test 18

Verdict: ACCEPTED

Test 19

Verdict: RUNTIME ERROR

Test 20

Verdict: RUNTIME ERROR

Test 21

Verdict: RUNTIME ERROR

Test 22

Verdict: RUNTIME ERROR

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: RUNTIME ERROR

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: WRONG ANSWER

Test 30

Verdict: WRONG ANSWER