2026/05/22

[LeetCode] 542 01 Matrix

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class Status {
public:
  int x, y, dis;
  Status(int _x, int _y, int _dis) : x(_x), y(_y), dis(_dis) {}
};

class Solution {
private:
  int N, M;
  vector<vector<int>> dis;
  int dirX[4] = {0, 1, 0, -1};
  int dirY[4] = {1, 0, -1, 0};

public:
  vector<vector<int>> updateMatrix(vector<vector<int>> &mat) {
    queue<Status> Q;
    N = mat.size();
    M = mat[0].size();
    dis.resize(N);
    for (int i = 0; i < N; i++) {
      dis[i].resize(M);
      for (int j = 0; j < M; j++) {
        if (mat[i][j] == 0) {
          Q.push(Status(i, j, 0));
          dis[i][j] = 0;
        } else
          dis[i][j] = INT_MAX;
      }
    }

    while (!Q.empty()) {
      Status cur = Q.front();
      Q.pop();
      for (int i = 0; i < 4; i++) {
        int dx = cur.x + dirX[i];
        int dy = cur.y + dirY[i];
        if (dx < 0 || dx >= N || dy < 0 || dy >= M)
          continue;
        if (dis[dx][dy] <= cur.dis + 1)
          continue;
        dis[dx][dy] = cur.dis + 1;
        Q.push(Status(dx, dy, cur.dis + 1));
      }
    }
    return dis;
  }
};