Next Greater Element Problem Statement

You are given an array arr of length N. For each element in the array, find the next greater element (NGE) that appears to the right. If there is no such greater element, return -1.

Input:

T N arr[0] arr[1] ... arr[N-1]

Output:

NGE[0] NGE[1] ... NGE[N-1]

Example:

Input:

1
3
1 3 2

Output:

3 -1 -1

Explanation:

For 1, 3 is the next greater element. 3 has no greater element to its right, so it returns -1. Similarly, 2 also returns -1.

Constraints:

1

Question

Next Greater Element Problem Statement

You are given an array arr of length N. For each element in the array, find the next greater element (NGE) that appears to the right. If there is no such greater element, return -1.

Input:

T 
 N 
 arr[0] arr[1] ... arr[N-1]

Output:

NGE[0] NGE[1] ... NGE[N-1]

Example:

Input:

1 
 3 
 1 3 2

Output:

3 -1 -1

Explanation:

For 1, 3 is the next greater element. 3 has no greater element to its right, so it returns -1. Similarly, 2 also returns -1.

Constraints:

1 <= T <= 10
1 <= N <= 10^5
0 <= arr[i] <= 10^9
Time Limit: 1 sec

Note:

Implement the function without printing anything; printing is already handled.

Accepted Answer

Given an array, find the next greater element to the right for each element. If no greater element, return -1.

Use a stack to keep track of elements in decreasing order.
Iterate through the array from right to left, popping elements from the stack until finding a greater element.
Store the next greater element in a result array.

Next Greater Element Problem Statement

Input:

Output:

Example:

Input:

Output:

Explanation:

Constraints:

Note:

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