GCJ2020-1A3: Square Dance

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

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

/// U R D L
pii ctrl[4] = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}};
vector<vector<int>> board;
int q, row, col;
lli sum;

int main(){

    int x;
    bool change;

    scanf("%d", &q);
    for(int k = 1; k <= q; ++k){
        scanf("%d %d", &row, &col);
        board.assign(row + 2, vector<int>(col + 2, 0));
        for(int i = 1; i <= row; ++i){
            for(int j = 1; j <= col; ++j){
                scanf("%d", &x);
                board[i][j] = x;
            }
        }

        sum = 0;
        change = true;
        while(change){
            change = false;
            vector<pii> fail;
            for(int i = 1; i <= row; ++i){
                for(int j = 1; j <= col; ++j){
                    sum += board[i][j];
                    if(board[i][j] != 0){
                        double mean;
                        int add = 0;
                        int cnt = 0;
                        for(int d = 0; d < 4; ++d){
                            int nr = i + ctrl[d].r;
                            int nc = j + ctrl[d].c;
                            if(nr > 0 && nr <= row && nc > 0 && nc <= col){
                                while(nr > 0 && nr <= row && nc > 0 && nc <= col){
                                    if(board[nr][nc] != 0){
                                        add += board[nr][nc];
                                        ++cnt;
                                        break;
                                    }
                                    nr += ctrl[d].r;
                                    nc += ctrl[d].c;
                                }
                            }
                        }
                        if(cnt != 0){
                            mean = (double)add / (double)cnt;
                            if(mean > board[i][j]){
                                fail.push_back({i, j});
                                change = true;
                            }
                        }
                    }
                }
            }
            for(auto x : fail){
                board[x.r][x.c] = 0;
            }
        }
        cout << "Case #" << k << ": " << sum << "\n";
    }

    return 0;
}