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程式語言 - LeetCode - C++ - 200. Number of Islands

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題目：


解答：

class Solution {
public:
    int numIslands(vector<vector<char>>& grid) {
        int m = grid.size();
        int n = grid[0].size();

        auto dfs = [&](this auto&& dfs, int i, int j) -> void {
            if (i < 0 || i >= m || j < 0 || j >= n || grid[i][j] == '0') {
                return;
            }

            grid[i][j] = '0';
            dfs(i + 1, j);
            dfs(i - 1, j);
            dfs(i, j + 1);
            dfs(i, j - 1);
        };

        int ans = 0;
        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                if (grid[i][j] == '1') {
                    ans += 1;
                    dfs(i, j);
                }
            }
        }

        return ans;
    }
};