[leetcode]-896. Monotonic Array（C语言）

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

bool isMonotonic(int* A, int ASize) {
    int i,j,k;
    if(ASize==1)
        return true;
    for(i=1;i<ASize;i++)
    {
        if(A[i]!=A[i-1])
            break;
    }
    if(i==ASize)
        return true;
    if(A[i]>A[i-1])
    {
        for(j=i+1;j<ASize;j++)
        {
            if(A[j]<A[j-1])
                return false;
        }
    }
    if(A[i]<A[i-1])
    {
        for(j=i+1;j<ASize;j++)
        {
            if(A[j]>A[j-1])
                return false;
        }
    }
    return true;
}