class Solution {
public:
    bool validMountainArray(vector<int>& arr) {
        if(arr.size() <= 2) return false;
        int arr_flag = 0;
        for(int i=1 ;i<arr.size();i++)
        {
            if(arr_flag == 0 && arr[i] > arr[i-1]) arr_flag = 1;
            if(arr_flag == 1 && arr[i] > arr[i-1]) continue;
            else if(arr_flag == 1 && arr[i] == arr[i-1])  return false;
            else if(arr_flag == 1 && arr[i] < arr[i-1])  arr_flag += 1;
            if(arr_flag == 2 && arr[i] < arr[i-1]) continue;
            else return false;
        }
        if(arr_flag == 2) return true;
        else return false;
    }
};

class Solution {
public:
    bool validMountainArray(vector<int>& arr) {
        if(arr.size()<=2) return false;
        int left = 0;
        int right = arr.size()-1;
        while( left<arr.size() && arr[left] < arr[left+1]) 
            left++;
        while(right > 0 && arr[right] < arr[right-1])
            right--;
        // cout<<left<<' '<<right;
        if(left == right && left!=0 && right!=arr.size()-1) return true;
        else return false;
    }
};