[剑指Offer] 65.矩阵中的路径

 1 class Solution {
 2 public:
 3     bool dfs(char* matrix, int rows, int cols, char* str, int i, int j){
 4         if(str == NULL || *str == ‘\0‘){
 5             return true;
 6         }
 7         bool ans = false;
 8         if((i>= 0) && (i < rows) && (j >= 0) && (j < cols) && (matrix[i * cols + j] == *str)){
 9             matrix[i * cols + j] = ‘\0‘;
10             ans = dfs(matrix, rows, cols, str + 1, i - 1, j)
11                   ||dfs(matrix, rows, cols, str + 1, i + 1, j)
12                   ||dfs(matrix, rows, cols, str + 1, i, j - 1)
13                   ||dfs(matrix, rows, cols, str + 1, i, j + 1);
14             matrix[i * cols + j] = *str;
15         }
16         return ans;
17     }
18     bool hasPath(char* matrix, int rows, int cols, char* str)
19     {
20         for(int i = 0;i < rows;i ++){
21             for(int j = 0;j < cols;j ++){
22                 if(dfs(matrix, rows, cols, str, i, j)){
23                     return true;
24                 }
25             }
26         }
27         return false;
28     }
29 };