PROG-T1011: Block Game

#include <iostream>
#include <vector>
#include <queue>
using namespace std;

#define pii pair<int, int>
#define r first
#define c second

/// R D
pii ctrl[2] = {{0, 1}, {1, 0}};
vector<vector<char>> board;
int row, col, q, score;

void PrintBoard(){
    for(int i = 1; i <= row; ++i){
        for(int j = 1; j <= col; ++j){
            cout << board[i][j] << " ";
        }
        cout << "\n";
    }
    return;
}

void FalltoBelow(pii s){
    if(board[s.r][s.c] != '-'){
        return;
    }
    int r = s.r - 1;
    int c = s.c;
    while(r > 0 && board[r][c] != '#' && board[r][c] != '-'){
        swap(board[r][c], board[r + 1][c]);
        --r;
    }
    return;
}

pii FallfromAbove(pii s){
    if(board[s.r][s.c] == '-' || board[s.r][s.c] == '#'){
        return s;
    }
    int r = s.r + 1;
    int c = s.c;
    while(r <= row && board[r][c] == '-'){
        swap(board[r][c], board[r - 1][c]);
        ++r;
    }
    return {r - 1, c};
}

void BFS(pii s){
    vector<pii> fall;
    queue<pii> q;
    fall.push_back(s);
    q.push(s);
    char t = board[s.r][s.c];
    board[s.r][s.c] = '-';
    score += 5;
    while(!q.empty()){
        int r = q.front().r;
        int c = q.front().c;
        q.pop();
        for(int i = 0; i < 2; ++i){
            int nr = r + ctrl[i].r;
            int nc = c + ctrl[i].c;
            if(nr <= row && nc <= col && board[nr][nc] == t){
                q.push({nr, nc});
                fall.push_back({nr, nc});
                board[nr][nc] = '-';
                score += 5;
            }
        }
    }
    for(auto x : fall){
        FalltoBelow(x);
    }
    return;
}

int main(){

    int r, c;
    char cmd;

    /// Get board
    scanf("%d %d", &row, &col);
    board.assign(row + 2, vector<char>(col + 2, '\0'));
    for(int i = 1; i <= row; ++i){
        for(int j = 1; j <= col; ++j){
            scanf(" %c", &cmd);
            board[i][j] = cmd;
        }
    }

    scanf("%d", &q);
    score = 0;
    for(int i = 0; i < q; ++i){
        scanf("%d %d %c", &r, &c, &cmd);
        ++r;
        ++c;

        /// Move L or R
        pii start = {r, c};
        pii target;
        switch(cmd){
        case 'L':
            target = {r, c - 1};
            break;
        case 'R':
            target = {r, c + 1};
            break;
        }

        /// Invalid moves
        if(target.c < 0 || target.c >= col || board[r][c] == '-' || board[r][c] == '#' || board[r][target.c] != '-'){
            score -= 5;
            continue;
        }

        /// Fall
        board[target.r][target.c] = board[start.r][start.c];
        board[start.r][start.c] = '-';
        target = FallfromAbove(target);
        FalltoBelow(start);

        /// Check blocks to destroy
        bool change = true;
        while(change){
            change = false;
            for(int j = 1; j <= row; ++j){
                for(int k = 1; k <= col; ++k){
                    for(int a = 0; a < 2; ++a){ /// Check R and D
                        int cr = j + ctrl[a].r;
                        int cc = k + ctrl[a].c;
                        if(board[j][k] != '-' && board[j][k] != '#' && cr <= row && cc <= col && board[j][k] == board[cr][cc]){
                            change = true;
                            BFS({j, k});
                        }
                    }
                }
            }
        }
    }
    cout << score << "\n";
    PrintBoard();

    return 0;
}