백준 7569번 토마토

아직 좌우앞뒤위아래 매커니즘이 뇌에 안박혀있어서 굉장히 원시적입니다. 

#define _CRT_SECURE_NO_WARNINGS
 
#include <iostream>
#include <queue>
 
using namespace std;
int box[104][104][104] = { 0, };
int x, y, z;
queue<pair<pair<int, int>, int>> myq;
 
bool isin(int a, int b, int c) {
    if (a >= 0 && b >= 0 && c >= 0 && a < x&&b < y&&c < z&&box[a][b][c] == 0)return true;
    else return false;
}
 
void bfs(int a, int b, int c) {
    if (isin(a - 1, b, c)) {
        box[a - 1][b][c] = 1;
        myq.push(make_pair(make_pair(a - 1, b), c));
    }
    if (isin(a + 1, b, c)) {
        box[a + 1][b][c] = 1;
        myq.push(make_pair(make_pair(a + 1, b), c));
    }
    if (isin(a, b - 1, c)) {
        box[a][b - 1][c] = 1;
        myq.push(make_pair(make_pair(a, b - 1), c));
    }
    if (isin(a, b + 1, c)) {
        box[a][b + 1][c] = 1;
        myq.push(make_pair(make_pair(a, b + 1), c));
    }
    if (isin(a, b, c - 1)) {
        box[a][b][c - 1] = 1;
        myq.push(make_pair(make_pair(a, b), c - 1));
    }
    if (isin(a, b, c + 1)) {
        box[a][b][c + 1] = 1;
        myq.push(make_pair(make_pair(a, b), c + 1));
    }
}
int main() {
    //freopen("test.txt", "r", stdin);
    cin >> x >> y >> z;
 
    for (int i = 0; i < z; i++) {
        for (int j = 0; j < y; j++) {
            for (int k = 0; k < x; k++) {
                cin >> box[k][j][i];
                if (box[k][j][i] == 1) {
                    myq.push(make_pair(make_pair(k, j), i));
                    
                }
 
            }
        }
    }
 
    
    int qsize, cnt = 0;
 
    while (!myq.empty()) {
 
        qsize = myq.size();
 
        for (int i = 0; i < qsize; i++) {
            bfs(myq.front().first.first, myq.front().first.second, myq.front().second);
            myq.pop();
        }
        if (myq.size() > 0)cnt++;
 
    }
    for (int i = 0; i < z; i++) {
        for (int j = 0; j < y; j++) {
            for (int k = 0; k < x; k++) {
                if (box[k][j][i] == 0) {
                    cout << "-1";
                    return 0;
                }
            }
        }
    }
    cout << cnt;
}