/*
 * @lc app=leetcode.cn id=695 lang=cpp
 *
 * [695] 岛屿的最大面积
 */

// @lc code=start
class Solution {
public:
    int maxAreaOfIsland(vector<vector<int>>& grid) {
        int m = grid.size(), n = grid[0].size();
        int res = 0;
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                if (grid[i][j] == 1) {
                    res = max(res, dfs(grid, i, j));
                }
            }
        }
        return res;
    }

    int dfs(vector<vector<int>>& grid, int i, int j) {
        if (i < 0 || j < 0 || i >= grid.size() || j >= grid[0].size()) return 0;
        if (grid[i][j] == 0) return 0;

        grid[i][j] = 0;

        return 1 + dfs(grid, i + 1, j) + dfs(grid, i - 1, j) + dfs(grid, i, j + 1) + dfs(grid, i, j - 1);
    }
};
// @lc code=end