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SQP6 Next Greatest Element I

Given an array arr[ ] of size N having elements, the task is to find the next greater element for each element of the array in order of their appearance in the array. Next greater element of an element in the array is the nearest element on the right which is greater than the current element. If there does not exist next greater of current element, then next greater element for current element is -1. For example, next greater of the last element is always -1.

Example 1:
Input: N = 4, arr[] = [1 3 2 4]
Output: 3 4 4 -1
Explanation:
In the array, the next larger element to 1 is 3 , 3 is 4 , 2 is 4 and for 4 ? since it doesn't exist, it is -1.

Example 2:
Input: N = 5, arr[] [6 8 0 1 3]
Output: 8 -1 1 3 -1
Explanation:
In the array, the next larger element to 6 is 8, for 8 there is no larger elements hence it is -1, for 0 it is 1 , for 1 it is 3 and then for 3 there is no larger element on right and hence -1.

Constraints:
- 1 ≤ N ≤ 10^6
- 0 ≤ Ai ≤ 10^18

Notes

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Thought Process

This is is the first varient of the Problem that based on the Stack adn Queue

        for(i to n){
            for(i+1 to n){
                find MAX Element
            }
        }
    

Every Iteration of i we checked if any element present into the Stack that is Smaller the arr[i] So simplly Removed all the element from the Stack that is smaller then arr[i].

Othe wise take the top element from the stack and put into the Visited Array at the Index of i

Dry Run

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Time Complexity:O(2N + 2N) ~ O(N) first loop for loop and Second for while loop
Space Complexity:O(N)+O(N) for Stack and VisitdArray.