题目地址：https://leetcode.com/problems/monotonic-array/description/
题目描述
Anarray is monotonic if it is either monotone increasing or monotone decreasing.
Anarray A is monotone increasing if for all i <= j, A[i] <= A[j]. An array A is monotone decreasing if for all i <= j, A[i] >= A[j].
Return true if and only if the given array A is monotonic.
Example 1:
Input: [1,2,2,3]
Output: true
Example 2:
Input: [6,5,4,4]
Output: true
Example 3:
Input: [1,3,2]
Output: false
Example 4:
Input: [1,2,4,5]
Output: true
Example 5:
Input: [1,1,1]
Output: true
Note:
- 1 <= A.length <= 50000
- -100000 <= A[i] <= 100000
题目大意
判断一个数组是不是单调的。单调包括单调递增和单调递减。
解题方法
用python的话，最快的方式应该是使用all，只用看连续两个数字之间的差值和0之间的比较就行了。
代码如下：
class Solution(object):
def isMonotonic(self, A):
"""
:type A: List[int]
:rtype: bool
"""
return self.isIncrease(A) or self.isDecrease(A)
def isIncrease(self, A):
return all(A[i] - A[i+1] >= 0 for i in range(len(A) - 1))
def isDecrease(self, A):
return all(A[i] - A[i+1] <= 0 for i in range(len(A) - 1))
1 2 3 4 5 6 7 8 9 10 11 12 13
DDKK.COM 弟弟快看-教程，程序员编程资料站，版权归原作者所有
本文经作者：负雪明烛 授权发布，任何组织或个人未经作者授权不得转发