896. Monotonic Array (easy)

Q:

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

A:

class Solution {
public:
    bool isMonotonic(vector<int>& A) {
        int n = A.size();
        if(n==0)
            return true;
        if(A[0] <= A[n-1])
        {
            return checkIncrease(A);
        }else{
            return checkDecrease(A);
        }
    }
private:
    bool checkIncrease(vector<int> &A)
    {
        for(int i =0;i<A.size()-1;++i)
        {
            if(A[i]>A[i+1])   
                return false;
        }
        return true;
    }
    bool checkDecrease(vector<int> &A)
    {
        for(int i =0;i<A.size()-1;++i)
        {
            if(A[i]<A[i+1])
                return false;
        }
        return true;
    }
};