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
}