find-peak-element-ii

 1 class Solution:
 2     """
 3     @param: A: An integer matrix
 4     @return: The index of the peak
 5     """
 6     def findPeakII(self, A):
 7         # write your code here
 8         m, n = len(A), len(A[0])
 9         left, right, up, down = 1, n - 2, 1, m - 2
10         while left + 1 < right and up + 1 < down:
11             if right - left > down - up:
12                 mid = (left + right) // 2
13                 max_index = self.find_max_in_col(A, mid, up, down)
14                 if self.is_peak(A, max_index, mid):
15                     return [max_index, mid]
16                 elif A[max_index][mid] < A[max_index][mid - 1]:
17                     right = mid
18                 else:
19                     left = mid
20             else:
21                 mid = (up + down) // 2
22                 max_index = self.find_max_in_row(A, mid, left, right)
23                 if self.is_peak(A, mid, max_index):
24                     return [mid, max_index]
25                 elif A[mid][max_index] < A[mid - 1][max_index]:
26                     down = mid
27                 else:
28                     up = mid
29         for i in range(up, down + 1):
30             for j in range(left, right + 1):
31                 if self.is_peak(A, i, j):
32                     return [i, j]
33         return [-1, -1]
34             
35     def is_peak(self, A, i, j):
36         return A[i][j] == max(A[i][j], A[i - 1][j], A[i + 1][j], A[i][j - 1], A[i][j + 1])
37         
38     def find_max_in_col(self, A, col, up, down):
39         index = down
40         for i in range(up, down):
41             if A[i][col] > A[index][col]:
42                 index = i
43         return index
44         
45     def find_max_in_row(self, A, row, left, right):
46         index = right
47         print(left, right)
48         for i in range(left, right):
49             if A[row][i] > A[row][index]:
50                 index = i
51         return index

 

转载于:https://www.cnblogs.com/liqiniuniu/p/11388914.html