Leetcode 498. 对角线遍历（DAY 300）---- 后端面试题

• • 原题题目
  • 代码实现（首刷自解 做了很久）

class Solution {
 public:
  vector findDiagonalOrder(vector>& mat) {
    vector ret;
    int level = 0, maxlevel = mat.size() + mat[0].size() - 2;
    bool dirup = true;
    int x = 0, y = 0;

    while (level <= maxlevel) {
      if (dirup) {
        x = min(static_cast(mat.size() - 1), level);
        y = level - x;
      } else {
        y = min(static_cast(mat[0].size() - 1), level);
        x = level - y;
      }
      while (x >= 0 && x < mat.size() && y >= 0 && y < mat[0].size()) {
        ret.emplace_back(mat[x][y]);
        if (dirup) {
          --x; ++y;
        } else {
          ++x; --y;
        }
      }
      ++level;
      dirup ^= true;
    }
    return ret;
  }
};