SOLVED: Given an array of integers arr, replace each element with its rank.

@moh_sa8

Sep '21

Given an array of integers arr, replace each element with its rank. The rank represents how large the element is. The rank has the following rules:

Rank is an integer starting from 1. The larger the element, the larger the rank. If two elements are equal, their rank must be the same. Rank should be as small as possible.

Example 1:

Input: arr = [40,10,20,30] Output: [4,1,2,3] Explanation: 40 is the largest element. 10 is the smallest. 20 is the second smallest. 30 is the third smallest. Example 2:

Input: arr = [100,100,100] Output: [1,1,1] Explanation: Same elements share the same rank.

@roosterboy HWS+

Sep '21

import Foundation

func rankArray(_ array: [Int]) -> [Int] {
    let sortedArray = Set(array).sorted()
    return array.map {
        sortedArray.firstIndex(of: $0)! + 1
    }
}

let arr = [40, 10, 20, 30]
print(rankArray(arr))
//prints [4, 1, 2, 3]

let arr2 = [100, 100, 100]
print(rankArray(arr2))
//prints [1, 1, 1]

let arr3 = [40, 10, 20, 30, 30, 10, 50, 70]
print(rankArray(arr3))
//prints [4, 1, 2, 3, 3, 1, 5, 6]

Edit: A little change to rankArray to account for the third example

@moh_sa8

Sep '21

@roosterboy

Thank you so much😍

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