{"id":468,"date":"2025-10-30T19:46:49","date_gmt":"2025-10-30T11:46:49","guid":{"rendered":"https:\/\/heyingnian.com\/?p=468"},"modified":"2025-10-30T19:47:16","modified_gmt":"2025-10-30T11:47:16","slug":"leetcode-994","status":"publish","type":"post","link":"https:\/\/heyingnian.com\/index.php\/2025\/10\/30\/leetcode-994\/","title":{"rendered":"\u8150\u70c2\u7684\u6a58\u5b50"},"content":{"rendered":"\n

\ud83d\udd17 \u8150\u70c2\u7684\u6a58\u5b50<\/h1>\n\n\n\n

\u9898\u76ee\u6765\u6e90<\/strong>\uff1a994. \u8150\u70c2\u7684\u6a58\u5b50 – \u529b\u6263\uff08LeetCode\uff09<\/a><\/a><\/p>\n\n\n\n

\n\n\n\n

\ud83d\udccc \u9898\u76ee\u63cf\u8ff0<\/h2>\n\n\n\n

\u5728\u7ed9\u5b9a\u7684 m x n<\/code> \u7f51\u683c grid<\/code> \u4e2d\uff0c\u6bcf\u4e2a\u5355\u5143\u683c\u7684\u503c\u542b\u4e49\u5982\u4e0b\uff1a<\/p>\n\n\n\n

    \n
  • 0<\/code>\uff1a\u7a7a\u5355\u5143\u683c<\/li>\n\n\n\n
  • 1<\/code>\uff1a\u65b0\u9c9c\u6a58\u5b50<\/strong><\/li>\n\n\n\n
  • 2<\/code>\uff1a\u8150\u70c2\u6a58\u5b50<\/strong><\/li>\n<\/ul>\n\n\n\n

    \u6bcf\u5206\u949f\uff0c\u6240\u6709\u8150\u70c2\u6a58\u5b50\u4f1a\u540c\u65f6<\/strong>\u5c06\u5176 \u4e0a\u4e0b\u5de6\u53f3<\/strong> \u76f8\u90bb\u7684\u65b0\u9c9c\u6a58\u5b50\u53d8\u6210\u8150\u70c2\u6a58\u5b50\u3002<\/p>\n\n\n\n

    \n

    \u8981\u6c42\uff1a\u8fd4\u56de \u76f4\u5230\u6ca1\u6709\u65b0\u9c9c\u6a58\u5b50\u4e3a\u6b62\u6240\u9700\u7684\u6700\u5c0f\u5206\u949f\u6570<\/strong>\u3002
    \u82e5\u4e0d\u53ef\u80fd\u8150\u70c2\u6240\u6709\u6a58\u5b50\uff0c\u8fd4\u56de -1<\/code>\u3002<\/p>\n<\/blockquote>\n\n\n\n

    \n\n\n\n

    \u2705 \u793a\u4f8b\u89e3\u6790<\/h2>\n\n\n\n

    \u793a\u4f8b 1\uff1a<\/strong><\/p>\n\n\n\n

    \"\"<\/div><\/figure>\n\n\n\n
    \u8f93\u5165\uff1agrid = [[2,1,1],[1,1,0],[0,1,1]]
    \u8f93\u51fa\uff1a4<\/code><\/pre>\n\n\n\n
    \u89e3\u91ca\uff1a<\/p>\n\n\n\n
      \n
    • \u7b2c 0 \u5206\u949f\uff1a\u521d\u59cb\u72b6\u6001\uff0c1 \u4e2a\u8150\u70c2\u6a58\u5b50\uff1b<\/li>\n\n\n\n
    • \u7b2c 1 \u5206\u949f\uff1a\u611f\u67d3 2 \u4e2a\uff1b<\/li>\n\n\n\n
    • \u7b2c 2 \u5206\u949f\uff1a\u518d\u611f\u67d3 2 \u4e2a\uff1b<\/li>\n\n\n\n
    • \u7b2c 3\u30014 \u5206\u949f\uff1a\u9010\u6b65\u611f\u67d3\u5269\u4f59\u6a58\u5b50\uff1b<\/li>\n\n\n\n
    • \u7b2c 4 \u5206\u949f\u540e\uff0c\u65e0\u65b0\u9c9c\u6a58\u5b50 \u2192 \u8fd4\u56de\u00a04<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n
      \u793a\u4f8b 2\uff1a<\/strong><\/p>\n\n\n\n
      \u8f93\u5165\uff1agrid = [[2,1,1],[0,1,1],[1,0,1]]
      \u8f93\u51fa\uff1a-1<\/code><\/pre>\n\n\n\n
      \u89e3\u91ca\uff1a\u5de6\u4e0b\u89d2\u7684\u6a58\u5b50\uff08\u7b2c 2 \u884c\u7b2c 0 \u5217\uff09\u88ab\u7a7a\u683c\u9694\u65ad\uff0c\u65e0\u6cd5\u88ab\u611f\u67d3 \u2192 \u6c38\u8fdc\u65b0\u9c9c<\/strong>\u3002<\/p>\n\n\n\n
      \u793a\u4f8b 3\uff1a<\/strong><\/p>\n\n\n\n
      \u8f93\u5165\uff1agrid = [[0,2]]
      \u8f93\u51fa\uff1a0<\/code><\/pre>\n\n\n\n
      \u89e3\u91ca\uff1a\u521d\u59cb\u65e0\u65b0\u9c9c\u6a58\u5b50\uff0c\u65e0\u9700\u7b49\u5f85 \u2192 \u8fd4\u56de 0<\/code>\u3002<\/p>\n\n\n\n
      \n\n\n\n
      \u26a0\ufe0f \u63d0\u793a<\/h2>\n\n\n\n
        \n
      • m == grid.length<\/code>\uff0cn == grid[i].length<\/code><\/li>\n\n\n\n
      • 1 <= m, n <= 10<\/code><\/li>\n\n\n\n
      • grid[i][j] \u2208 {0, 1, 2}<\/code><\/li>\n<\/ul>\n\n\n\n
        \n
        \ud83d\udccc \u7f51\u683c\u89c4\u6a21\u5c0f\uff0c\u4f46\u7b97\u6cd5\u9700\u5177\u5907\u901a\u7528\u6027\uff08\u53ef\u6269\u5c55\u81f3\u66f4\u5927\u89c4\u6a21\uff09\u3002<\/p>\n<\/blockquote>\n\n\n\n
        \n\n\n\n
        \ud83d\udca1 \u89e3\u6cd5\uff1a\u591a\u6e90 BFS\uff08\u5e7f\u5ea6\u4f18\u5148\u641c\u7d22\uff09\u2014\u2014 O(mn) \u65f6\u95f4\uff0cO(mn) \u7a7a\u95f4<\/h2>\n\n\n\n
        class Solution {\n    private static final int FRESH = 1;   \/\/ \u65b0\u9c9c\u6a58\u5b50\n    private static final int ROTTEN = 2;  \/\/ \u8150\u70c2\u6a58\u5b50\n    private static final int[][] DIRECTIONS = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};\n\n    public int orangesRotting(int[][] grid) {\n        Queue<int[]> queue = new LinkedList<>();\n        int freshCount = 0;\n        int m = grid.length;\n        int n = grid[0].length;\n\n        \/\/ \u521d\u59cb\u5316\uff1a\u5c06\u6240\u6709\u8150\u70c2\u6a58\u5b50\u5165\u961f\uff0c\u7edf\u8ba1\u65b0\u9c9c\u6a58\u5b50\u6570\u91cf\n        for (int i = 0; i < m; i++) {\n            for (int j = 0; j < n; j++) {\n                if (grid[i][j] == FRESH) {\n                    freshCount++;\n                } else if (grid[i][j] == ROTTEN) {\n                    queue.offer(new int[]{i, j});\n                }\n            }\n        }\n\n        \/\/ \u82e5\u65e0\u65b0\u9c9c\u6a58\u5b50\uff0c\u76f4\u63a5\u8fd4\u56de 0\n        if (freshCount == 0) return 0;\n\n        int minutes = 0;\n\n        \/\/ \u591a\u6e90 BFS\n        while (!queue.isEmpty() && freshCount > 0) {\n            int size = queue.size();\n            boolean infected = false; \/\/ \u6807\u8bb0\u672c\u8f6e\u662f\u5426\u6709\u65b0\u6a58\u5b50\u88ab\u611f\u67d3\n\n            for (int i = 0; i < size; i++) {\n                int[] cell = queue.poll();\n                int x = cell[0], y = cell[1];\n\n                for (int[] dir : DIRECTIONS) {\n                    int nx = x + dir[0];\n                    int ny = y + dir[1];\n\n                    \/\/ \u68c0\u67e5\u662f\u5426\u8d8a\u754c\uff0c\u4e14\u4e3a\u65b0\u9c9c\u6a58\u5b50\n                    if (nx >= 0 && nx < m && ny >= 0 && ny < n && grid[nx][ny] == FRESH) {\n                        grid[nx][ny] = ROTTEN; \/\/ \u8150\u70c2\n                        freshCount--;          \/\/ \u65b0\u9c9c\u6570\u51cf 1\n                        queue.offer(new int[]{nx, ny});\n                        infected = true;\n                    }\n                }\n            }\n\n            if (infected) minutes++; \/\/ \u4ec5\u5f53\u6709\u65b0\u611f\u67d3\u65f6\uff0c\u65f6\u95f4 +1\n        }\n\n        \/\/ \u82e5\u4ecd\u6709\u65b0\u9c9c\u6a58\u5b50\uff0c\u8bf4\u660e\u65e0\u6cd5\u5168\u90e8\u8150\u70c2\n        return freshCount == 0 ? minutes : -1;\n    }\n}<\/code><\/pre>\n\n\n\n
        \u2705 \u5173\u952e\u70b9<\/strong>\uff1a<\/p>\n\n\n\n
          \n
        • \u591a\u6e90 BFS<\/strong>\uff1a\u521d\u59cb\u6240\u6709\u8150\u70c2\u6a58\u5b50\u540c\u65f6\u4f5c\u4e3a\u8d77\u70b9\uff1b<\/li>\n\n\n\n
        • \u6309\u5c42\u904d\u5386<\/strong>\uff1a\u6bcf\u5206\u949f\u5904\u7406\u5f53\u524d\u6240\u6709\u8150\u70c2\u6a58\u5b50\u7684\u90bb\u5c45\uff1b<\/li>\n\n\n\n
        • \u8ba1\u6570\u4f18\u5316<\/strong>\uff1a\u7528\u00a0freshCount<\/code>\u00a0\u8ddf\u8e2a\u5269\u4f59\u65b0\u9c9c\u6a58\u5b50\uff0c\u907f\u514d\u6700\u540e\u904d\u5386\u6574\u4e2a\u7f51\u683c\u3002<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n
          \ud83d\udcca \u590d\u6742\u5ea6\u5206\u6790<\/h2>\n\n\n\n
            \n
          • \u65f6\u95f4\u590d\u6742\u5ea6<\/strong>\uff1aO(m \u00d7 n)<\/code>
            \u6bcf\u4e2a\u5355\u5143\u683c\u6700\u591a\u5165\u961f\u4e00\u6b21\uff0cBFS \u904d\u5386\u4e00\u6b21\u7f51\u683c\u3002<\/li>\n\n\n\n
          • \u7a7a\u95f4\u590d\u6742\u5ea6<\/strong>\uff1aO(m \u00d7 n)<\/code>
            \u6700\u574f\u60c5\u51b5\u4e0b\uff08\u5168\u4e3a\u8150\u70c2\u6a58\u5b50\uff09\uff0c\u961f\u5217\u5b58\u50a8\u6240\u6709\u5355\u5143\u683c\u3002<\/li>\n<\/ul>\n\n\n\n
            \n\n\n\n
            \ud83e\udde9 \u89e3\u9898\u601d\u8def<\/h2>\n\n\n\n
            \u4e3a\u4ec0\u4e48\u7528 BFS \u800c\u4e0d\u662f DFS\uff1f<\/h3>\n\n\n\n
              \n
            • \u611f\u67d3\u662f\u201c\u540c\u6b65\u6269\u6563\u201d<\/strong>\uff1a\u6bcf\u5206\u949f\u6240\u6709\u8150\u70c2\u6a58\u5b50\u540c\u65f6<\/strong>\u611f\u67d3\u90bb\u5c45\uff1b<\/li>\n\n\n\n
            • BFS \u5929\u7136\u652f\u6301\u201c\u6309\u5c42\u6269\u5c55\u201d<\/strong>\uff0c\u6bcf\u5c42\u5bf9\u5e94\u4e00\u5206\u949f\uff1b<\/li>\n\n\n\n
            • DFS \u662f\u6df1\u5ea6\u4f18\u5148\uff0c\u65e0\u6cd5\u81ea\u7136\u6a21\u62df\u201c\u5e76\u884c\u611f\u67d3\u201d\u8fc7\u7a0b\u3002<\/li>\n<\/ul>\n\n\n\n
              \u591a\u6e90 BFS \u7684\u672c\u8d28<\/h3>\n\n\n\n
              \n
              \u628a\u6240\u6709\u521d\u59cb\u8150\u70c2\u6a58\u5b50\u770b\u4f5c\u201c\u7b2c 0 \u5c42\u201d\uff0c\u5b83\u4eec\u7684\u90bb\u5c45\u662f\u201c\u7b2c 1 \u5c42\u201d\uff0c\u4f9d\u6b64\u7c7b\u63a8\u3002<\/p>\n<\/blockquote>\n\n\n\n
              \u8fd9\u4e0e\u201c\u4ece\u591a\u4e2a\u8d77\u70b9\u540c\u65f6\u5f00\u59cb\u7684\u6700\u77ed\u8def\u5f84\u201d\u95ee\u9898\u5b8c\u5168\u4e00\u81f4\u3002<\/p>\n\n\n\n
              \u8fb9\u754c\u60c5\u51b5\u5904\u7406<\/h3>\n\n\n\n
              \u60c5\u51b5<\/th>\u5904\u7406\u65b9\u5f0f<\/th><\/tr><\/thead>
              \u65e0\u65b0\u9c9c\u6a58\u5b50<\/td>\u76f4\u63a5\u8fd4\u56de 0<\/code><\/td><\/tr>
              \u6709\u65b0\u9c9c\u6a58\u5b50\u4f46\u65e0\u6cd5\u5230\u8fbe<\/td>BFS \u7ed3\u675f\u540e freshCount > 0<\/code> \u2192 \u8fd4\u56de -1<\/code><\/td><\/tr>
              \u7f51\u683c\u5168\u4e3a\u7a7a<\/td>freshCount = 0<\/code> \u2192 \u8fd4\u56de 0<\/code><\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"
              \ud83d\udd17 \u8150\u70c2\u7684\u6a58\u5b50 \u9898\u76ee\u6765\u6e90\uff1a994. \u8150\u70c2\u7684\u6a58\u5b50 – \u529b\u6263\uff08LeetCode\uff09 \ud83d\udccc \u9898\u76ee\u63cf\u8ff0 \u5728\u7ed9\u5b9a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12,40],"tags":[60,59,31,14],"class_list":["post-468","post","type-post","status-publish","format-standard","hentry","category-algorithm","category-graph","tag-graphs","tag-bfs","tag-array","tag-algorithm"],"_links":{"self":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/468","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/comments?post=468"}],"version-history":[{"count":1,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/468\/revisions"}],"predecessor-version":[{"id":470,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/posts\/468\/revisions\/470"}],"wp:attachment":[{"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/media?parent=468"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/categories?post=468"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/heyingnian.com\/index.php\/wp-json\/wp\/v2\/tags?post=468"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}