LeetCode: Word Search

自己的思路对的，一直过不了large是因为把visit的建立放在循环最里层，导致每次都建一个两维vector耗了大量的时间。太傻逼了。。

 1 class Solution {
 2 public:
 3     bool dfs(string word, int dep, int maxdep, vector<vector<char>> &board, int x, int y, vector<vector<bool>> &visit, int dir[4][2]) {
 4         if (dep == maxdep) return true;
 5         int m = board.size();
 6         int n = board[0].size();
 7         for (int i = 0; i < 4; i++) {
 8             int xx = x + dir[i][0];
 9             int yy = y + dir[i][1];
10             if (xx >= 0 && xx < m && yy >= 0 && yy < n && board[xx][yy] == word[dep] && !visit[xx][yy]) {
11                 visit[xx][yy] = true;
12                 if (dfs(word, dep+1, maxdep, board, xx, yy, visit, dir)) return true;
13                 visit[xx][yy] = false;
14             }
15         }
16     }
17     bool exist(vector<vector<char> > &board, string word) {
18         // Start typing your C/C++ solution below
19         // DO NOT write int main() function
20         int dir[4][2] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
21         int m = board.size();
22         if (!m) return false;
23         int n = board[0].size();
24         if (!word.size()) return true;
25         vector<vector<bool>> visit(m, vector<bool>(n, false));
26         for (int i = 0; i < m; i++) {
27             for (int j = 0; j < n; j++) {
28                 if (word[0] == board[i][j]) {
29                     visit[i][j] = true;
30                     bool flag = false;
31                     if (dfs(word, 1, word.size(), board, i, j, visit, dir)) return true;
32                     visit[i][j] = false;
33                 }
34             }
35         }
36         return false;
37     }
38 };

 1 public class Solution {
 2     public bool Exist(char[,] board, string word) {
 3         int[,] dir = new int[4, 2]{{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
 4         int m = board.GetLength(0);
 5         int n = board.GetLength(1);
 6         if (m == 0 || n == 0) return false;
 7         bool[,] visit = new bool[m, n];
 8         for (int i = 0; i < m; i++) {
 9             for (int j = 0; j < n; j++) {
10                 if (word[0] == board[i, j]) {
11                     visit[i, j] = true;
12                     bool flag = false;
13                     if (dfs(word, 1, word.Length, board, i, j, visit, dir)) return true;
14                     visit[i, j] = false;
15                 }
16             }
17         }
18         return false;
19     }
20     public bool dfs(string word, int dep, int maxdep, char[,] board, int x, int y, bool[,] visit, int[,] dir) {
21         if (dep == maxdep) return true;
22         int m = board.GetLength(0);
23         int n = board.GetLength(1);
24         for (int i = 0; i < 4; i++) {
25             int xx = x + dir[i, 0];
26             int yy = y + dir[i, 1];
27             if (xx >= 0 && xx < m && yy >= 0 && yy < n && board[xx, yy] == word[dep] && !visit[xx, yy]) {
28                 visit[xx, yy] = true;
29                 if (dfs(word, dep+1, maxdep, board, xx, yy, visit, dir)) return true;
30                 visit[xx, yy] = false;
31             }
32         }
33         return false;
34     }
35 }

View Code

posted @ 2013-04-23 03:40 ying_vincent 阅读(567) 评论(0) 收藏举报

刷新页面返回顶部