山峰数组指, 先严格递增, 再严格递减的数组. 现给到一个数组, 找到一个连续子数组, 使得该子数组是山峰数组, 输出最长的该子数组的长度.
要求只遍历一遍数组, 并且空间复杂度为O(1)
想了10分钟知道怎么写, 写了40分钟才debug没问题, 提交了5次前后, 我觉得我是一个sb.
class Solution: def longestMountain(self, arr: List[int]) -> int: result = 0 if len(arr) <= 2: return 0 result = 0 first_index = 0 pre_num = arr[0] left = 0 sign = 0 for i in range(1, len(arr)): # print(f"current index: {i}, sign = {sign}, left = {left}") current_num = arr[i] if pre_num < current_num: if sign == 0: pass else: tmp = i - 1 - left + 1 result = max(tmp, result) left = i - 1 sign = 0 elif pre_num == current_num: if sign == 0: left = i else: tmp = i - 1 - left + 1 result = max(tmp, result) # print(left, i, tmp) left = i sign = 0 else: if sign == 0: if left == i - 1: left = i else: sign = 1 tmp = i - left + 1 result = max(tmp, result) # print(left, i, tmp) else: tmp = i - left + 1 result = max(tmp, result) # print(left, i, tmp) pre_num = current_num return result