{"id":2904,"date":"2022-04-21T22:42:56","date_gmt":"2022-04-21T14:42:56","guid":{"rendered":"https:\/\/www.zeroheart.xyz\/wordpress\/?p=2904"},"modified":"2022-04-26T00:12:07","modified_gmt":"2022-04-25T16:12:07","slug":"%e7%ae%97%e6%b3%95%e5%9f%ba%e7%a1%80%e7%ac%ac8%e5%a4%a9","status":"publish","type":"post","link":"https:\/\/www.zeroheart.xyz\/wordpress\/?p=2904","title":{"rendered":"\u7b97\u6cd5\u57fa\u7840\u7b2c8\u5929"},"content":{"rendered":"\n

bfs\u7ee7\u7eed\uff0c\u7c7b\u4f3c\u70c2\u6a58\u5b50\uff0c\u4f7f\u7528\u6269\u6563\u6cd5\uff0c\u8fd9\u91cc8\u4e2a\u65b9\u5411\u53ef\u4ee5\u6269\u6563<\/p>\n\n\n\n

1091. \u4e8c\u8fdb\u5236\u77e9\u9635\u4e2d\u7684\u6700\u77ed\u8def\u5f84<\/a><\/p>\n\n\n\n


\/**
<\/em> 1091. \u4e8c\u8fdb\u5236\u77e9\u9635\u4e2d\u7684\u6700\u77ed\u8def\u5f84
<\/em> \u7ed9\u4f60\u4e00\u4e2a n x n \u7684\u4e8c\u8fdb\u5236\u77e9\u9635 grid \u4e2d\uff0c\u8fd4\u56de\u77e9\u9635\u4e2d\u6700\u77ed \u7545\u901a\u8def\u5f84 \u7684\u957f\u5ea6\u3002\u5982\u679c\u4e0d\u5b58\u5728\u8fd9\u6837\u7684\u8def\u5f84\uff0c\u8fd4\u56de -1 \u3002
<\/em>
<\/em> \u4e8c\u8fdb\u5236\u77e9\u9635\u4e2d\u7684 \u7545\u901a\u8def\u5f84 \u662f\u4e00\u6761\u4ece \u5de6\u4e0a\u89d2 \u5355\u5143\u683c\uff08\u5373\uff0c(0, 0)\uff09\u5230 \u53f3\u4e0b\u89d2 \u5355\u5143\u683c\uff08\u5373\uff0c(n - 1, n - 1)\uff09\u7684\u8def\u5f84\uff0c\u8be5\u8def\u5f84\u540c\u65f6\u6ee1\u8db3\u4e0b\u8ff0\u8981\u6c42\uff1a
<\/em>
<\/em> \u8def\u5f84\u9014\u7ecf\u7684\u6240\u6709\u5355\u5143\u683c\u90fd\u7684\u503c\u90fd\u662f 0 \u3002
<\/em> \u8def\u5f84\u4e2d\u6240\u6709\u76f8\u90bb\u7684\u5355\u5143\u683c\u5e94\u5f53\u5728 8 \u4e2a\u65b9\u5411\u4e4b\u4e00 \u4e0a\u8fde\u901a\uff08\u5373\uff0c\u76f8\u90bb\u4e24\u5355\u5143\u4e4b\u95f4\u5f7c\u6b64\u4e0d\u540c\u4e14\u5171\u4eab\u4e00\u6761\u8fb9\u6216\u8005\u4e00\u4e2a\u89d2\uff09\u3002
<\/em> \u7545\u901a\u8def\u5f84\u7684\u957f\u5ea6 \u662f\u8be5\u8def\u5f84\u9014\u7ecf\u7684\u5355\u5143\u683c\u603b\u6570\u3002
<\/em>
<\/em>
<\/em>
<\/em> \u793a\u4f8b 1\uff1a
<\/em>
<\/em>
<\/em> \u8f93\u5165\uff1agrid = [[0,1],[1,0]]
<\/em> \u8f93\u51fa\uff1a2
<\/em> \u793a\u4f8b 2\uff1a
<\/em>
<\/em>
<\/em> \u8f93\u5165\uff1agrid = [[0,0,0],[1,1,0],[1,1,0]]
<\/em> \u8f93\u51fa\uff1a4
<\/em> \u793a\u4f8b 3\uff1a
<\/em>
<\/em> \u8f93\u5165\uff1agrid = [[1,0,0],[1,1,0],[1,1,0]]
<\/em> \u8f93\u51fa\uff1a-1
<\/em>
<\/em>
<\/em> \u63d0\u793a\uff1a
<\/em>
<\/em> n == grid.length
<\/em> n == grid[i].length
<\/em> 1 <= n <= 100
<\/em> grid[i][j] \u4e3a 0 \u6216 1
<\/em>
<\/em> * <\/em>@author <\/em><\/strong>zeroheart
<\/em> *
<\/em> *\/
<\/em>public class Question1091 {
    public int shortestPathBinaryMatrix(int[][] grid) {
        int n = grid.length;
        if(grid[0][0]!=0){
            return -1;
        }else if( n == 1){
            return 1;
        }

        Queue<int[]> queue = new LinkedList();
        queue.add(new int[]{0, 0});

        int[] dx = {-1, -1, -1, 0, 0, 1, 1, 1};
        int[] dy = {-1, 0, 1, -1, 1, -1, 0, 1};
        int res = 1;


        while (!queue.isEmpty()){
            res++;
            int size = queue.size();
            for(int s = 0; s<size; s++){
                int[] poll = queue.poll();
                int x = poll[0];
                int y = poll[1];

                for(int i = 0; i<8; i++){
                    int nx = dx[i] + x;
                    int ny = dy[i] + y;

                    if(nx>=0 && nx<n && ny>=0 && ny<n){
                        if(grid[nx][ny] == 0){

                            if(nx == n-1 && ny == n-1){
                                return res;
                            }

                            grid[nx][ny] = 1;
                            queue.add(new int[]{nx, ny});
                        }
                    }

                }
            }

        }
        return -1;
    }
}<\/pre>\n\n\n\n
130. \u88ab\u56f4\u7ed5\u7684\u533a\u57df<\/a><\/p>\n\n\n\n
\u8fd9\u9898\u7406\u89e3\u9898\u76ee\u610f\u601d\u6bd4\u8f83\u91cd\u8981\uff0c<\/p>\n\n\n\n
\u548c\u8fb9\u754c\u4e0a\u7684O\u76f4\u63a5\u6216\u8005\u95f4\u63a5\u76f8\u8fde\u7684\uff0c\u5c31\u662f\u6ca1\u88ab\u5305\u56f4\u7684\uff0c\u5148\u6807\u8bb0A\uff0c\u5728\u8fd8\u539fO\uff0c\u5176\u4ed6\u7684\u5904\u7406\u4e3aX<\/pre>\n\n\n\n

\/**
<\/em> 130. \u88ab\u56f4\u7ed5\u7684\u533a\u57df
<\/em> \u7ed9\u4f60\u4e00\u4e2a m x n \u7684\u77e9\u9635 board \uff0c\u7531\u82e5\u5e72\u5b57\u7b26 'X' \u548c 'O' \uff0c\u627e\u5230\u6240\u6709\u88ab 'X' \u56f4\u7ed5\u7684\u533a\u57df\uff0c\u5e76\u5c06\u8fd9\u4e9b\u533a\u57df\u91cc\u6240\u6709\u7684 'O' \u7528 'X' \u586b\u5145\u3002
<\/em>
<\/em>
<\/em> \u793a\u4f8b 1\uff1a
<\/em>
<\/em>
<\/em> \u8f93\u5165\uff1aboard = [[\"X\",\"X\",\"X\",\"X\"],[\"X\",\"O\",\"O\",\"X\"],[\"X\",\"X\",\"O\",\"X\"],[\"X\",\"O\",\"X\",\"X\"]]
<\/em> \u8f93\u51fa\uff1a[[\"X\",\"X\",\"X\",\"X\"],[\"X\",\"X\",\"X\",\"X\"],[\"X\",\"X\",\"X\",\"X\"],[\"X\",\"O\",\"X\",\"X\"]]
<\/em> \u89e3\u91ca\uff1a\u88ab\u56f4\u7ed5\u7684\u533a\u95f4\u4e0d\u4f1a\u5b58\u5728\u4e8e\u8fb9\u754c\u4e0a\uff0c\u6362\u53e5\u8bdd\u8bf4\uff0c\u4efb\u4f55\u8fb9\u754c\u4e0a\u7684 'O' \u90fd\u4e0d\u4f1a\u88ab\u586b\u5145\u4e3a 'X'\u3002 \u4efb\u4f55\u4e0d\u5728\u8fb9\u754c\u4e0a\uff0c\u6216\u4e0d\u4e0e\u8fb9\u754c\u4e0a\u7684 'O' \u76f8\u8fde\u7684 'O' \u6700\u7ec8\u90fd\u4f1a\u88ab\u586b\u5145\u4e3a 'X'\u3002\u5982\u679c\u4e24\u4e2a\u5143\u7d20\u5728\u6c34\u5e73\u6216\u5782\u76f4\u65b9\u5411\u76f8\u90bb\uff0c\u5219\u79f0\u5b83\u4eec\u662f\u201c\u76f8\u8fde\u201d\u7684\u3002
<\/em> \u793a\u4f8b 2\uff1a
<\/em>
<\/em> \u8f93\u5165\uff1aboard = [[\"X\"]]
<\/em> \u8f93\u51fa\uff1a[[\"X\"]]
<\/em>
<\/em>
<\/em> \u63d0\u793a\uff1a
<\/em>
<\/em> m == board.length
<\/em> n == board[i].length
<\/em> 1 <= m, n <= 200
<\/em> board[i][j] \u4e3a 'X' \u6216 'O'
<\/em>
<\/em> * <\/em>@author <\/em><\/strong>zeroheart
<\/em> *
<\/em> *\/
<\/em>public class Question130 {
    public void solve(char[][] board) {
        int n = board.length;
        if (n == 0) {
            return;
        }
        int m = board[0].length;
        \/\/ \u548c\u8fb9\u754c\u4e0a\u7684O\u76f4\u63a5\u6216\u8005\u95f4\u63a5\u76f8\u8fde\u7684\uff0c\u5c31\u662f\u6ca1\u88ab\u5305\u56f4\u7684\uff0c\u5148\u6807\u8bb0A\uff0c\u5728\u8fd8\u539fO\uff0c\u5176\u4ed6\u7684\u5904\u7406\u4e3aX
        Queue<int[]> queue = new LinkedList<int[]>();
        for (int i = 0; i < n; i++) {
            if (board[i][0] == 'O') {
                queue.offer(new int[]{i, 0});
                board[i][0] = 'A';
            }
            if (board[i][m - 1] == 'O') {
                queue.offer(new int[]{i, m - 1});
                board[i][m - 1] = 'A';
            }
        }
        for (int i = 1; i < m - 1; i++) {
            if (board[0][i] == 'O') {
                queue.offer(new int[]{0, i});
                board[0][i] = 'A';
            }
            if (board[n - 1][i] == 'O') {
                queue.offer(new int[]{n - 1, i});
                board[n - 1][i] = 'A';
            }
        }

        int[] dx = new int[]{-1, 1, 0, 0};
        int[] dy = new int[]{0, 0, -1, 1};

        while (!queue.isEmpty()) {
            int[] cell = queue.poll();
            int x = cell[0], y = cell[1];
            for (int i = 0; i < 4; i++) {
                int mx = x + dx[i], my = y + dy[i];
                if (mx < 0 || my < 0 || mx >= n || my >= m || board[mx][my] != 'O') {
                    continue;
                }
                queue.offer(new int[]{mx, my});
                board[mx][my] = 'A';
            }
        }
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (board[i][j] == 'A') {
                    board[i][j] = 'O';
                } else if (board[i][j] == 'O') {
                    board[i][j] = 'X';
                }
            }
        }
    }
}<\/pre>\n\n\n\n
797. \u6240\u6709\u53ef\u80fd\u7684\u8def\u5f84<\/a><\/p>\n\n\n\n
\u8fd9\u4e2a\u548c\u5168\u6392\u5217\u7684\u6a21\u7248\u7c7b\u4f3c\uff0c\u4f7f\u7528\u56de\u6eaf\u6cd5\uff0c\u4e3b\u8981\u5f00\u59cb\u6211\u4e0d\u80fd\u770b\u61c2\u4ed6\u7684\u6709\u5411\u56fe<\/p>\n\n\n\n
class Solution {\n    public List<List<Integer>> allPathsSourceTarget(int[][] graph) {\n        List<List<Integer>> list = new ArrayList<>();\n        List<Integer> path = new ArrayList<>();\n        path.add(0);\n        dfs(graph, 0, path, list);\n        return list;\n    }\n    \n    public void dfs(int[][] graph, int x, List<Integer> path, List<List<Integer>> list){\n        if(x == graph.length - 1){\n            list.add(new ArrayList<>(path));\n            return;\n        }\n\n        for(int i = 0; i < graph[x].length; i++){\n            path.add(graph[x][i]);\n            dfs(graph, graph[x][i], path, list);\n            path.remove(path.size() - 1);\n        }\n    }\n\n}<\/pre>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
bfs\u7ee7\u7eed\uff0c\u7c7b\u4f3c\u70c2\u6a58\u5b50\uff0c\u4f7f\u7528\u6269\u6563\u6cd5\uff0c\u8fd9\u91cc8\u4e2a\u65b9\u5411\u53ef\u4ee5\u6269\u6563 1091. \u4e8c\u8fdb\u5236\u77e9\u9635\u4e2d\u7684\u6700\u77ed\u8def\u5f84 \/** 1091 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[155],"tags":[197],"_links":{"self":[{"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2904"}],"collection":[{"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2904"}],"version-history":[{"count":7,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2904\/revisions"}],"predecessor-version":[{"id":3069,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2904\/revisions\/3069"}],"wp:attachment":[{"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2904"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2904"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2904"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}