BOJ2206: 벽 부수고 이동하기

작성일

https://www.acmicpc.net/problem/2206

  • 2월동안 187문제 풀기(지난달 누적 87개) (16/187)
  • 의외로 헤맨 BFS문제
  • 반성해야한다.
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#include <bits/stdc++.h>
using namespace std;

int N, M;
char arr[1001][1001];
char dp[1001][1001][2];
struct Point {
  int x, y, b;
};

inline bool bound(int x, int y) {
  return x >= 0 && x < N && y >= 0 && y < M;
}
const int dx[4] = {0,0,1,-1};
const int dy[4] = {1,-1,0,0};

int main() {
  ios::sync_with_stdio(false);
  cin >> N >> M;
  for(int i = 0; i < N ; i++) {
    cin >> arr[i];
  }

  queue<Point> q;
  q.push({0,0,1});
  if (N == 1 && M == 1) {
    cout << 1;
    return 0;
  }

  int depth = 0;
  while(q.size()) {
    int sz = q.size();
    depth++;
    for(int s = 0; s < sz; s++) {
      Point cur = q.front(); q.pop();
      for(int dir = 0; dir < 4; dir++) {
        int nx = cur.x + dx[dir];
        int ny = cur.y + dy[dir];
        if(!bound(nx,ny) || dp[nx][ny][cur.b] || (!cur.b && arr[nx][ny] == '1')) continue;
        if(nx == N-1 && ny == M-1) {
          cout << depth+1;
          return 0;
        }
        if (arr[nx][ny] == '0') {
          q.push({nx,ny,cur.b});
          dp[nx][ny][cur.b] = 1;
        } else {
          q.push({nx,ny,0});
          dp[nx][ny][0] = 1;
        }
      }
    }
  }
  cout << -1;
}