1299. Replace Elements with Greatest Element on Right Side

Problem

Given an array arr, replace every element in that array with the greatest element among the elements to its right, and replace the last element with -1.

After doing so, return the array.

Example 1:

Input: arr = [17,18,5,4,6,1]
Output: [18,6,6,6,1,-1]

Constraints:

• 1 <= arr.length <= 10^4
• 1 <= arr[i] <= 10^5

Problem Summary

Given an array arr, replace each element with the greatest element on its right; if it is the last element, replace it with -1. After completing all replacement operations, return this array.

Note:

• 1 <= arr.length <= 10^4
• 1 <= arr[i] <= 10^5

Solution Approach

• Given an array, replace every element with the greatest element to its right, and fill the last position with -1. Finally, output the changed array.
• Easy problem; just operate according to the problem statement.

Code

func replaceElements(arr []int) []int {
	j, temp := -1, 0
	for i := len(arr) - 1; i >= 0; i-- {
		temp = arr[i]
		arr[i] = j
		j = max(j, temp)
	}
	return arr
}