class Solution { private: int search(int x, int y, int threshold, vector<vector <int>>& matrix) { /* 从当前节点出发,可以到的格子 */ if (x < 0 || x >= matrix.size() || y < 0 || y >= matrix[0].size() || matrix[x][y] || !underThreshold(x, y, threshold)) { return 0; } matrix[x][y] = 1; re...