LeetCode [896] Monotonic Array

An array is monotonic if it is either monotone increasing or monotone decreasing.

An array 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. 1 <= A.length <= 50000
2. -100000 <= A[i] <= 100000

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class Solution { public: bool isMonotonic(vector<int>& A) { int order = 0;//0 unknown; 1 increasing; 2 decreasing for(int i=1; i<A.size(); ++i) { if(A[i]>A[i-1]){ if(order==0) order = 1; if(order==2) return false; } if(A[i]<A[i-1]){ if(order==0) order = 2; if(order==1) return false; } } return true; } };