class Solution {

public:

    bool validMountainArray(vector<int>& A) {

        if(A.size()<) return false;

        int max = A[], max_id = ;

        for(int i=; i<A.size(); ++i)

        {

            if(A[i]>max)

            {

                max = A[i];

                max_id = i;

            }

        }

        if(max_id== || max_id==A.size()-) return false;//errr..

        for(int i=; i<A.size(); i++)

        {

            if(i<max_id && A[i]<=A[i-]) return false;//errr...

            if(i>max_id && A[i]>=A[i-]) return false;//errr..

        }

        return true;

    }

};

class Solution {

public:

    bool validMountainArray(vector<int>& A) {

        int i=, n=A.size()-, j=n;

        while(i<n- && A[i]<A[i+]) i++;

        while(j> && A[j-]>A[j]) j--;

        return i> && i==j && j<n;

    }

};