백준 17070번 C++ 풀이

https://www.acmicpc.net/problem/17070

//
//  main.cpp
//  ps
//
//  Created by MOZZET PC on 22/07/2019.
//  Copyright © 2019 Noondate. All rights reserved.
//

#include <iostream>
#include <vector>
#include <cstring>
#include <queue>
#include <map>
#include <climits>
#include <algorithm>
#include <stack>

using namespace std;

int n;
int buffer[17][17];
int answer = 0;

bool is_range(int x, int y) {
  return (0 <= x && x < n && 0 <= y && y < n && buffer[x][y] == 0);
}

bool is_end(int x, int y) {
  return (x == n-1 && y == n-1 );
}
void horizontal(int x, int y);
void vertical(int x, int y);
void cross_v(int x, int y);

// 가로
void horizontal(int x, int y) {

  if (!(is_range(x, y) && is_range(x, y +1))) {
    return;
  }
  if (is_end(x, y) || is_end(x, y+1)){
    answer++;
    return;
  }
  horizontal(x, y+1);
  cross_v(x, y+1);
}

// 세로

void vertical(int x, int y) {

  if (!(is_range(x, y) && is_range(x+1, y))) {
    return;
  }
  if (is_end(x, y) || is_end(x+1, y)){
    answer++;
    return;
  }

  vertical(x+1, y);
  cross_v(x+1, y);
}

void cross_v(int x, int y) {
  if (!(is_range(x, y) && is_range(x + 1, y +1) && is_range(x, y+1) && is_range(x+1, y))) {
    return;
  }
  if (is_end(x, y) || is_end(x + 1, y+1)){
    answer++;
    return;
  }

  horizontal(x+1, y+1);
  vertical(x+1, y+1);
  cross_v(x+1, y+1);
}



int main(int argc, const char * argv[]) {
  cin >> n;

  for (auto x = 0; x < n; x++) {
    for (auto y = 0; y<n; y++) {
      cin >> buffer[x][y];
    }
  }

  horizontal(0, 0);

  cout << answer;

  return 0;
}